I just tried Bomgar and it would connect but on the remote end I just got a black screen and a cursor that didn’t move the regular one and didn’t end when I closed it on the client end.
TeamViewer would be my next guess, but I installed that from the website and it downloaded version 9 for some reason (both from Chrome and Safari) , I got version 14 on there by going straight to this page to download. https://www.teamviewer.com/en-us/download/mac-os/. It prompted me to open Accessibility settings and add TeamViewer there.
After connection, it prompted me to add it to screen recording as well and launched the window for me. Finally then it connected and allowed me access. So it worked, but it was even more steps than with Mojave.
Security is great, but Apple and these companies need to figure out a way that lopw level users can be protected and not go through all these hoops.