Monterey poor performance?

I already reinstall OS, clean install, disk repair, reseted nvram and SMC, downgraded to Big Sur again (still the same problem, not expecting this).

Even with a new OS, nothing installed, the symptoms are already there.

Sounds like a hardware problem. If you have erased and reinstalled, and also did the same with the Big Sur and still have problems, I can't imagine there is not some sort of problem. You can try running Apple Diagnostics, or take it to an Apple Store for evaluation.

The EtreCheck report indicates slow SSD performance.

That would explain why reinstalling Big Sur and not installing anything else still showed bad performance.

Again, you have something wrong with your Mac and it is likely the SSD or something related to the I/O to the SSD.

The report also shows you have installed a lot of useless dreck which will slow down your Mac.

If you install everything you had before, you'll never figure out where the problem may be.

You have to erase the drive and reinstall whatever OS you want to test. Do not install anything.

Use the built-in apps to create documents to save and open, edit, re-save.

If it doesn't perform satisfactorily, take it to an Apple Store or Authorize Repair center for evaluation.

You can also try running Apple Diagnostics. Since it might be an issue with the SSD, AD might actually find something.

If everything is fine, then you can migrate your user data from your backup. Since you are not using Time Machine, I have no idea how you would restore just your user data. It's simple with Time Machine and Migration Assistant.

If it still runs ok, you can reinstall only your necessary software to do what you need to do on the Mac.

You don't need Bitdefender, avformac, NordVPN, CleanMyMac, …

If after you have all necessary software installed, you can waste your time installing the useless garbageware noted above, but I would suggest you not do that.

The Biggest Issue is " CleanMyMac " as per screen shot above.

Even if one did a Wipe and Clean Install of Monterey or Big Sur and then either reinstalled the CMM or use Migration Assist afterwords - the Problem is CMM is there.

Please take the time to read the first 600 posting on the ASC Forums to see the extent of the damages this specific Application does and will do to the OS.

Strongly suggest Removing this software ONLY via the Developers Specific Instructions.

https://discussions.apple.com/search?q=cleanmymac

I agree with MrHoffman. The write speeds are way too low. Try running the Apple Hardware Test and see if there's any indication of what's causing it; How to use Apple Hardware Test on your Mac - Apple Support

There's another strange item in the report: 2021-12-29 00:53:55 photolibraryd High CPU Use

If you don't have a Photos library on the Mac I don't think that process should be running as it related directly to a Photos library.

Please download and run EtreCheck, and then share the report to the clipboard. Then open a new reply here, and press the button that looks like a printed page (additional text, text attachment) to get a text input box big enough to paste the hardware and software configuration report here, and paste the report here.

As mentioned above, cleaning apps have been seen to cause performance issues, and removing cleaning apps, add-on security apps, add-on VPN client apps, and related apps can sometimes resolve performance and stability issues. There can be other hardware and software causes, of course.

There are some hardware configurations which runs poorly, such as the iMac 21.5” 8 GB with a hard disk drive configuration, which is just going to be slow, absent an external SSD or similar work. Hard disks are slow. And 8 GB isn’t enough to mask the slow.

The EtreCheck report will provide a better idea of what hardware and software is involved here.

That’s starting to look like bad hardware. That SSD is getting slow. Maybe DriveDx or Apple Diagnostics shows something odd?

Next stop is probably a discussion with Apple Support.

i can see by your screenshot that you have clean my mac x installed. IMHO, that could be the root of the problems. it is well known to cause issues within macOS while providing zero benefits. you would do well to uninstall it following the developer's instructions. and while i agree that monterey was probably engineered with apple silicon in mind, i have not noticed any issues with it on my intel iMac. actually, things feel a little snappier than it did with big sur and/or catalina.

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is desshoigned solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer, school or bank's servers, they are useless from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Former Malware Distributor Kape Technologies Now Owns ExpressVPN, CyberGhost, Private Internet Access, Zenmate, and a Collection of VPN “Review” Websites. 

Uninstall Bitdefender according to the developer's instructions. I would also uninstall NordVPN.

Write speeds are still low. Give this a day or so to rebuild, post re-install, and check again. Some of the apps showing high CPU are apps that analyze and sync cached data. That an app related to the bridge has crashed is not good, though. If this doesn’t stabilize in a day or three, you’re likely headed for a repair.

I’m going to be straight to the point:

As it turns out, macOS Monterey was designed for the new Apple SoC’s and the performance difference is day and night.

I had to upgrade to see it for myself.

My old iMac required a visit to the Genius bar.

👉🏼 Call 1-800-MY-APPLE or get help here. 

I have a 2-13 MacPro and Monterey works great. Only "problem" I has was that I had an non-Apple SSD installed and could not upgrade to Monterey. I put the Apple SSD back in and update that to Monterey. Then I reinstalled the non=Apple SSD and updated that to Monterey and all was well.

My performance issue with Monterey was not nearly as severe on my 2020 MacBook Air, but I noticed the cooling fan running much of the time (most noticably when a screen saver was on) and choppy graphics.

I am pleased to find that my problems seem to have been resolved with the update of 12.2.