What is going on with Safari in Sequoia 15.3.2?

Instagram and Facebook constantly/repeatedly reload to the point of being completely unusable (starts with the bar up top saying "This website was reloaded because a problem occurred," will work for a bit but many videos will be black reading "Sorry, we're having trouble playing this video," then shortly thereafter will go through a short burst of several attempts to load and reload, then gray screens on "a problem repeatedly occurred on ____." Not the worst sites to not function, but I do like YouTube....

Youtube started off a few days ago by bottlenecking during the ads and after a few seconds it would jump to the end/"skip" (okay, not complaining....). But then the videos themselves started having trouble. Spinny spinny spinny try to load. Then back to the thumbnail, with the play icon. Hit play. "An error occurred. Please try again later."

Speed tests more or less seem fine. Downloaded Chrome, everything works fine.

This has all been in the last few days. I updated from a slightly earlier version of Sequoia but don't know which, though a fairly recent one as this is a newly acquired refurbished m4 mini and I updated upon migration.

The following is a tangent, but it is quite frustrating to drop $1600 on a new whip, only to find the search function even more broken than before, Safari only half working, and many of my totally mainstream software no longer running natively or properly and/or takes a latex glove and some vaseline to get installed, and by the time I verify it is baseline usable I've passed the 14 days trade-in window so I now have 2 disappointing machines (previously had an m1 with 16gb ram). Not to mention that my system still overloads in Logic even with 32gb RAM and the bus power drive eject issue persists as well. Why is the Apple ecosystem becoming increasingly dysfunctional? Regretting this purchase.