Why is Mac OS (Sonoma/Sequoia) stuttering and lagging and applications crashing?

I just upgraded to Sequoia, but the problems continue.

Avast One found no significant virus or malware threats in a deep scan of the hard disc

1) The Finder cannot locate any files, just a few random ones, not even the files I am actually looking at

2) Typing is very slow. My fingers are stiff, but the OS can’t keep up with me.

3) Opening and closing any applications and files brings on the Rainbow Wheel of Death

4) The cursor is stuttering. If I try to move an object, I end up moving something else, or the object gets stuck to the cursor and falls off in the wrong place.

5) If I pull open a directory window, it gets stuck

6) If I use a browser and move the page up or down, everything disappears or it crashes

7) In trying to post this very question, my question disappeared. Error code: RESULT_CODE_HUNG

Processor is a 3 GHz 6-Core Intel Core i5

Graphics Card is a Radeon Pro 570X with 4 GB

The is still 672 GB available

I’m about to throw this piece of fei wu out the window

Any ideas? Is this happening to anybody else?