Thanks Mel. The instructions in the link you included don't seem to apply to me because none of this has changed my target version or build # settings, probably because I have never let anything finish downloading.
So far, this is what I have learned in my awful experience with Windows Insider: I can stay in the program, but opt out of getting build previews. Then everything seems to be fine -- no attempt to send me a preview of anything Windows 11. BUT, if I go with "leave the program," it seems to lose my opt-out choice and the darned previews start trying to download again -- even though it shows me having left the program!
So, I have had to pause updates and close the update window, then use the first step in the procedure to block Windows 11: 1. You need to stop wuauserv and bits, so they don't immediately recreate the directory you're going to delete in step 2, THEN (step 2 that we did before) empty the downloads folder in Windows>Software Distribution> Downloads, then REJOIN Windows Insider (!) because only then can I have an active setting to opt out of previews, THEN unpause updates, then all is well. But I will start my own post soon to try to find out how to rid my computer of whatever hangs on when you try to leave Windows Insider and are even told that you have left it. My need is to figure out how to completely exit this "Hotel California:"
"Relax," said the night man
"We are programmed to receive
You can check out any time you like
But you can never leave"