Using 12.0.1 (21A558) (RC), Teams will not work if I receive an incoming video stream. Audio based calls work fine, however, as soon as someone joins a Teams session and sends video, Teams will immediately crash. In earlier Monterey Betas it would crash maybe half of the time, but, a restart of Teams would likely let it work. However, with later betas, and with the RC, I am completely unable to run Teams on macOS with an incoming video. Tried running from the command line to get useful information, nothing, but, the logs that Teams generates itself show the crashes and it's 100% repeatable. At the moment, the only way I can use Teams is if I run it in a Linux or Windows virtual machine. (2019 MacPro)

Telnet was removed from macOS about 3 years ago. You won't find it in macOS Big Sur, Catalina, Mojave or macOS High Sierra. There are some alternatives in packaging systems such as "homebrew" but, the preference is to not use telnet due to the inherent security risks of doing so. If you think you need telnet, see if whatever you are accessing can use ssh instead. It's also possible to do some things using netcat (nc), which is installed by default.