The B650M is a smaller size and therefore has less features, but overall they seem similar. Biggest difference would be the integrated SSD heatsink and better VRM design + cooling of the non-M version. Also the second SSD slot being connected to the CPU instead of the chipset, if you ever want to put in two M.2 drives. One thing to watch out for is that both of these boards use a Realtek LAN chip which sometimes can be problematic with Linux.
They use XDG Desktop Portal, which makes video and audio capture system level instead of application level to enhance security. When a program wants to record your screen you get a pop up to choose which screen/window to share. After that the app can only see that window or screen.