The bios you refer to was for the earlier N series, pretty much everything you need to know about that series can be found in my very old post here
The Gen 8 will only take 16GB RAM, I think from distant memory this was a CPU limitation, cpu supported 32GB but that’s across 4 slots.
Good to capture this stuff on the Gen 8 though, thanks!
If you are looking for a proper solution then checkout AC infinity, that’ll give you everything you need I expect.
Otherwise you’re looking at a self build option of a fan controller and an appropriate power supply, I just used some relatively quiet highish airflow fans in my rack run at a pretty consistent speed using a basic fan controller I 3D printed a bracket for, I might turn them up a bit in the summer if the temps are showing high…
r/homelab is not the sub to gain basic PC or research skills, if you don’t have them then and the ability to do basic googling then you shouldn’t be posting here. This is not r/techsupport
A fundamental question isn’t being asked here, why are you not plugging the pi in to your router/switch? Your router has a DHCP server which is why WiFi works, it’s the same for wired. If we can understand your use case then we can help you better…
I used to run windows 7 pro (really you need a pro version to get RDP) it was 100% rock solid, did everything it needed to do, was very easy to setup and maintain. If doing this you should obviously use a newer version but forced updates will be your enemy, so google how to disable them but yes for most using a non server OS is fine. However this sub is about home labs, which is meant for learning enterprise software, you’re best posting over in r/homeserver or somewhere else I expect