Yeah, I’d be looking at the cache/optimization stuff first too. That’s usually where the “everything suddenly feels possessed” nonsense starts. I had one last week where the admin was laggy as hell after a couple plugin updates, and it turned out to be two plugins both trying to be clever with JS defer/minify. Front end was only slightly weird, but wp-admin was a mess until I shut one of them off. Of course the host support did the usual “we don’t see any issue” routine. If you already rolled one back and it helped a bit, that’s probably not nothing. I’d still test with all cache layers off for a bit — plugin cache, server cache, CDN if you’ve got it — just to see if the weirdness disappears. If it does, you’ve got your culprit-ish. If not, then yeah, it might be one of those stupid hosting days after all.
ToolDecision
Tools, compared and explained
ToolDecision
Tools, compared and explained