Sorry to hear that. I installed manjaro i3 community on my other laptop yesterday evening. Will see if I run into similar problems. Did you modify the standard config files that comes with the install?
One thing that helped me with some transparency/shadow issue with zoom and screensharing was to change the option of the following line in the i3 config file
exec --no-startup-id picom -C
where option -C: Disable shadow effects on panels and docks
https://wiki.archlinux.org/index.php/Picom#Disable_shadows_for_some_windows
Maybe worth another shot, sorry that I can’t be of more help.