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.
That monitor will hold it back. 1080p wouldn’t be bad if modern games run without TAA blur, but most games require it. Even a cheap 144hz IPS 1440p will give you a better experience.