iATKOS | United Kingdom

Just upgraded my early 2011 MBP to Sonoma. First time doing it and had a hell of a time. After finally getting and installing all the root patches, it is very sluggish, basically unusable. Should I install Ventura or earlier instead? Also, how can I verify that it can actually use the 16g or RAM, I upgraded it myself years ago (had 8g originally) and I’m worried I didn’t get it from a reputable source.

Thank you in advance for your help.