Update: 2 more possible causes:
-max size of pst is 50GB, so my 1.6GB pst should be fine.... however several times in recent months MS Outlook 2019 says I have reached max size, so I keep having to delete emails or their attachments. Why would it say this limit is reached? When I go to DOS and do "dir \outlook" it says:
14/08/2022 03:53 PM 1,651,721,216 Outlook.pst
-I contacted TotalAV, and they kindly did a remote session on my PC, and did a lot of tests, and they concluded TotalAV is not the cause of my "not responding" errors. They suggested it was most likely due to "heavy" apps. While I do have a few apps, the only 4 I use regularly are Word, Excel, Outlook and Brave Brower (I got same error when I used Google Chrome). I provide you with attached screendump to review.