I have been using vim for a long time and have never had a problem with my mouse scrolling and clicking.
Recently, I noticed the mouse was sporadic and no longer scrolling. I have made no changes to my .vimrc for a long while.
The only thing I can think of was maybe an update to my OS, which was recently upgraded to Ventura, but that still would be just a cause and not a solution.
It seems everything I look up just refers to adding mouse=a to my .vimrc, but that has been there for a long time.
I wondered if maybe there was an update to iTerm2, but then I decided to check this out in Terminal and I get the same issues.
I tried different variations of set mouse=a based on recommendations from other posts.
I also tried making changes in my iTerm2, but as stated this is also happening in Terminal.
I worked on reducing my .vimrc to practically nothing, but there were always two "set" properties I kept...
I realized I need to remove these even though it makes no sense at all.
What I discovered was that removing the ttymouse did the trick...
Once I commented out this line as shown above, and re-ran Vim, this issue resolved itself in both Terminal and iTerm2.