The easy way to get a clean copy is to download it directly from Microsoft. You can generate a valid download link using the follwing website (just make sure the domain of the generated link points to Microsoft and nothing bad can happen)
\https://tb.rg-adguard.net/public.php
As for the activation, I have found that the My Digital Life Forums have good activators available usually:
https://forums.mydigitallife.net/forums/kms-and-other-tools.51/
Edit: Sorry it looks like TechBench is dead, but this site seems to work the same way:
You haven’t mentioned what sort of access link or speed you have, that seems very relevant here.
For my 1Gbit/s fiber connection the Edgerouter 6P has been pretty good. It has an SFP port and can route 1 Gbit/s of traffic without issue and my dual-stack setup works well too.
The only significant downside is that its switching is slow, it has no hw support. So I put my NAS on a separate subnet instead so that the traffic to it can be routed instead.