Odd behaviour may be anything, they will let you know if component will be buggy or not. Regarding the result, you will need to be watchful during first few months.
There's no need to be. Doing bios update should be mandatory. All this platform is new and they are fixing plethora of bugs with each new bios version. The good news is that bios update can be done often from windows, by simply clicking on "Bios update" or by downloading it to USB stick and launching the update from the bios screen.
So, it's easy. And it's likely that you will be doing it yourself too.
https://pg.asrock.com/mb/AMD/B650E%20PG ... x.asp#BIOS
As you can check latest bios is from 3rd March and for your CPU was obligatory. (ver 1.18)
The same may happen overtime with your GPU. Life is not only about drivers
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Unstable memory would be worse, you will see if there will be random crashes...
That fee is high, when I was building PCs, which is now about ten years ago, the fee which I charged was around $25.
As a last thing, lots of errors comes in later due to microsoft "fixes". Just recently I was watching saving one my file on SSD, which took whooping 2 minutes. But it's known error, hopefully they will fix it soon - if that would be too booring, I can remove their fix. Yep, Windows 11 here, says hello.