Report Etrecheck pro about Imac 2017 4k retina

As P. Phillips suggested we need the full report. Please add it according to this user tip: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community

Pay particular attention to the "Full Disk Access" section.

With a Full Copy of the Etrecheck Report we maybe able to see what is actually happening on this computer

Important, giving the application Full Disc Access will probably give a more Meaningful Report with much more Details about the computer Hardware and Software

The EtreCheck report shows the Performance is Excellent.

It appears Spotlight is having trouble indexing the drive. That is probably caused by Avast.

All third-party AV software is actually Malware in and of itself. They are Trojan Horses because they claim to provide protection, but all they ever do is cause problems.

As you're already been told get rid of Avast. 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 designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Uninstall Avast according to the developer's instructions. Afterware rerun Etrecheck to verify that all of the Avast support files have been removed. If not remove them manually.

Very Good point by @Barney-15E

There are no Windows-like Viruses that affect macOS.

The only thing this software is protecting is the Bank Account of this Developer. That is aside from the problems this software will cause on this computer

Please help me figure out what this report is telling me.

After numerous re-installations Finder under 12.4 continues to malfunction: frequently doesn’t load all desktop icons, fails to shut down or restart, program loads stall, won’t relaunch, etc. This happens with both users and in safe mode. It’s always hit or miss as to what will work.

When I try to restore from Time Machine it takes me back to last year sometime. When I find a more recent system backup on Mac HD - data it wants me to use Migration Assistant.

So, I know some of the things I've done wrong, but I'm old, slow and out of practice and would really like some help.

Many thanks!

To be fair to the Original Owner of this question, it is suggested to Open a New Question of your own.

Do supply are reliable and accurate information regarding the Computer, Version OS macOS , Context and what steps you have attempted to solve this situation.

By opening a new question, the User ( you ) will probably receive a lot of assistance specific to this computer issue

sorry wrong thread