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.

VRMs (voltage regulator modules) are what bring the power to the CPU and these can get quote hot on high power processors. If you look around the socket on a motherboard, usually above and opposite the RAM, they are the big square/rectangle shaped components. Most high-performance motherboards have heatsinks on top of them to keep them from overheating, which your MB does not have.

Poweramp for music also. Worth the price, you can also skip the Play Store by buying it on the dev’s website if you prefer