kerneltask high CPU usage frequently, computer gets very slow

Two major things:

1) You are running CleanMyMac which is notorious for causing all sorts of problems with macOS. Uninstall it by following the developer's instructions. Anti-virus apps, cleaning/optimizer apps, and third party security software are not needed on a Mac and usually causes more problems than they solve since they interfere with the normal operation of macOS. macOS already has great built in security especially when the user also practices safe computing habits as outlined in this excellent article written by a respected forum contributor:

Effective defenses against malware and other threats - Apple Community

2) You are also running very low on free drive storage space. You should always have at least 20GB+ of free storage space available at all times for the normal operation of macOS. Some workloads may require having even more free space available. If you run out of free storage space on an APFS volume, then it can become impossible to delete anything to make more room due to how the APFS file system works.

If you still have problems, then run EtreCheck again and post the new report so we can make sure CMM was completely removed and look for any other possible issues.

I, too, recommend evicting CMM with extreme prejudice. For over 20 years the macOS has been self-cleaning and self-maintaining with elegant, automated routines that take care of all the housekeeping needed. They even defrag.

Third-party scamware that claim to clean, optimize, tune up, or find your Mac a mate are only interfering with the elegance you paid Apple to build into the operating system. The results are slowdowns and instability.

Try restarting your computer more often that every 16 days.\:

System Software:

macOS Ventura 13.0 (22A380)

Time since boot: About 16 days

This drive data is concerning:

Performance:

System Load: 20.40 (1 min ago) 22.55 (5 min ago) 21.06 (15 min ago)

Nominal I/O usage: 23.11 MB/s

File system: 73.24 seconds

Write speed: 35 MB/s

Read speed: 795 MB/s

Both are far under nominals but the Write speed is abysmal, actually slower by half than the sorry, under-spec 5400-rpm mech hard drive that came in my 2012 Macbook Pro.

Both should be showing four digits with that SSD spec. First rerun EtreCheck after evictiing CleanMyMac. I've sen CMM slow drive perforamcne in other reports.

Is those numbers do not improve, restart the computer in Safe Mode:

How to use safe mode on your Mac

and let it sit unused in Safe Mode for 1-2 hours. That might help with doing some tidying up of the SSD.

And I agree with HWTech that the tiny amount on free space on your internal drive could be a significant issue.

As you can see, removing CMM did increase the read speeds significantly. I don't see any of the normal software issues although you do have one or two things I don't recognize. You are a bit behind on your macOS updates though. The main problem is the extremely slow write speed of your SSD which is reported as 121 MB/s, but should at least be 1,500 MB/s or more. To check the health of the SSD, run DriveDX and post the complete text report here using the "Additional Text" icon which looks like a piece of paper. Unfortunately the Apple SSDs don't provide much health information, but maybe it will be enough to confirm a bad SSD, however, it probably doesn't really matter since the SSD is integrated into the Logic Board.

You can try running Disk Utility First Aid on the hidden Container to see if there are any issues with the file system which may be causing this. Within Disk Utility you may need to click "View" and select "Show All Devices" so the hidden Container appears on the left pane of Disk Utility. Even if First Aid says everything is "Ok", click "Show Details" and scroll through the report looking for any unfixed errors. If there are any unfixed errors listed, then you can try running First Aid from Internet Recovery Mode, otherwise you will need to erase the whole physical SSD followed by re-installing macOS & restoring from a backup.

Also disconnect all external devices in case one of them is causing a problem.

You can also try running the Apple Diagnostics to see if any hardware issues are detected. Unfortunately the diagnostics don't detect many hardware failures, so the only useful result is one which shows a failure.

Performing a clean install of macOS may be necessary. A clean install means first erasing the whole physical drive, then reinstalling macOS making sure to test the laptop before installing any third party apps or restoring from a backup. The only third party app you would want to use is EtreCheck to once more check the speed of the internal SSD after the clean install. You could also use Black Magic Speed Test. If the SSD's write speed is still below 1,500 MB/s, then you have a hardware issue with the laptop. If the write speed is Ok with a clean install, then you can try restoring from a backup and testing again. If the write speed drops below 1,500 MB/s, then something in that backup is most likely causing a problem.

Have you considered ditching Chrome?

Top Processes Snapshot by CPU:

Process (count) CPU (Source - Location)

Google Chrome Helper (Renderer) (57) 25.30 % (Google LLC) 😱

EtreCheckPro 18.88 % (Etresoft, Inc.)

WindowServer 12.38 % (Apple)

coreaudiod 8.54 % (Apple)

CAReportingService 5.58 % (Apple)

Top Processes Snapshot by Memory:

Process (count) RAM usage (Source - Location)

Google Chrome Helper (Renderer) (57) 7.95 GB (Google LLC) 😱

VTDecoderXPCService (4) 1.44 GB (Apple)

EtreCheckPro 985 MB (Etresoft, Inc.)

com.apple.WebKit.WebContent (2) 730 MB (Apple)

Google Chrome 474 MB (Google LLC)

I don't know if that would help the hard drive issue, but Chrome is a well-known resource hog on both Win and Mac computers. It also seems to me to be too active when in the background.

At least try quitting Chrome when you are not using it.