If you have both these problems
- system tray icons disappear
- system tray icons do not respond to right-clicking
then I think you need to investigate the applications concerned [Telegram, Discord, Steam?].
It might also be worth displaying & testing the system tray icons of some WIndows components so you might be able to discount the OS misbehaving.
Few applications have system tray icons and those that do contain their own instructions for displaying them.
Perhaps those applications have support sites & user forums that might assist you.
Best of luck,
Denis