That ATX board would be great. The mATX B650M PG is also better than the previous one, it is good enough. If you can find the B650M-HDV/M.2 in stock that is even better if you don’t need 3 m.2 slots.

That monitor was indeed a lucky deal. It looks to be a good combination for this setup.

The draft is pretty good. Only a few points to consider changing:

• That is an entry level Motherboard which may limit your upgrades in the future. It overheats with a 16 core ryzen 9.
• The ram size is good, but the speed and latencies are just as important nowadays. A 6000 MT/s CL30 Expo ram could improve CPU performance, but it’s a kind of OC so not every combination is fully stable at the highest speeds.
• Especially with competitive and indie games it’s easy to run them at high FPS. I would consider getting a 1440p high refresh rate (144+ Hz) monitor if you don’t have one already. It’s a huge upgrade coming from 1080p60Hz.