Yeah, other than the PBO, other things doesn't make sense for your use case.
Pretty much all the recent buyers I see in the forums got 3000 ready B450 boards. That shouldn't be a problem, esp. when someone is gonna help building this rig.
So, last minute switched to Intel. The flight sim software apparently does not make use of AMDs multi core, multi thread advantages. So, Intel with higher clock speed is still faster. Plus, from what I have read, overclocking is better with Intel.
Final build. Prices may be a bit higher than online, but that's OK.
Also, looking to change the PSU to 650 watts to save maybe 1K.