I’d disable all the Internet plugs, as a test.
I suspect that one of those—probably an old one, obviously—is what you’re having issues with.
To test that, create a new login (System Preferences > Users & Groups > add a new user, and log into that, and test Safari.
There are a lot of 32-bit apps around, and those won’t work. You’ll want to figure out which you need and must upgrade, which you don’t need and can remoce, and which you might hace to migrate to some other app if there’s no upgrade available.
Microsoft Office looks to old to work, for instance.
There are enough older apps here that wiping, migrating just files and docs and not apps, and re-loading current software, might be the easier approach.
Here’s a tool that works well for finding older apps: Go64. You may (will) have to download that tool on another Mac, and transfer it over to the problem Mac, then go hunting for the older apps, and decide which you’re using and will need to upgrade or to replace, and which of the older apps can be removed.