Can't change sequence settings and other bugs

When I want to change sequence settings, the window opens but when I click "okay" or "cancel" the button does not work. Even if I just open the window and make no changes, the buttons do not work.

I want to change sequence settings from portrait to square, to landscape - for the different mediums where we post our social media.

Also another bug - I cannot mark in and out points on the clips in the source monitor.

My machine is really really slow and it should not be (specs attached)

Premiere struggles now with our 1Dx MK iii footage, it never used to.

iPhone 13 Pro footage also struggles more than ANYTHING. Shot in 4k 60fps HDR.

I have stopped using normal Premiere because it can't even open the projects before crashing, BETA is far more stable because it at least works.

I really hope these bugs can be fixed.

I use a LaCie 2Tb SSD and another Mechanical LaCie 8Tb drive to edit off of.

Only recently (in the passed 6 months or so) has Premiere been really very bad to use.

Will really appreciate ANY form of help.