Applications (e.g. Safari, MS Excel, etc) go into “not responding” mode before they initially start per the Activity Monitor

App in dock will bounce for a long time, then stop bouncing. After awhile, the app will open (as the Activity monitor shows 'Not Responding' then working, then 'Not Responding' over and over again). Once open, App works fine. And if app is closed, then reopened, it'll open immediately. It's only the initial opening after a Restart or Start with power button that takes a long time.

I don't know when the problem started, but it's been going on since at least earlier this year (or longer). I just lived with it (or rarely shutdown/restarted the iMac). But opening the Activity Monitor yesterday and watching what's happening, I saw why it was taking so long. The iMac has had a least a couple of MacOS upgrades, but no difference to excruciating slow initial opening of apps.

Review of earlier posts suggests running EtreCheck. I've done so and attached the report below. Any help or suggestions would be appreciated. My alternative is to take it local Apple Genius Bar, but I thought I'd ask here first.