Unusable iMac?

I just installed Ventura on my mid 2011 21.5 in iMac (upgraded with Micron SSD, 12 Gb RAM). I could not go back to some older version (I tried Big Sur, but OCLP would not install).

Everything seems to be OK, even BT and WIFI connections. BUT I am starting to "see" several things:

  • My mouse has a too long delay. Up to 1 sec reaction time, and then "jumping" from point to point. No way to edit pictures with that, for example (just clicking icons is a pain). But using a USB mouse improves just slightly.

  • Streamed video is also lagging, cut. Facebook, X, Instagram... I cannot watch these. Of course, also not Netflix & co.

  • Photo Booth: Camera not working (but: Face time is)

Is there any setting in Ventura I am missing, to reduce CPU usage?

Where can I report these things to OCLP (maybe they'll find a fix)?

I am afraid, I have to go back to position one and retry Big Sur :(

Author: @AGBDesign_es