Thanks for replying!
I have also already read through the So you have 500Mbps-1Gbps fiber and need a router READ THIS FIRST pinned post, but it doesn't help much with actually choosing hardware - the OP just says that "a RPi is an option" and "this no-longer-available all-in-one PC is an option", and the HW mentioned in the replies has the same problems as that in the enthusuast HW post in that it's either not available anymore or not capable of (>)1Gbit. As for the point of the post though, I am aware that I'm looking for a pretty powerful machine and am ready to spend some coin.
As for the other post you linked, I'm not sure what I'm looking at. There seems to be a lot of people suggesting not-yet-supported HW, and a lot of it is a little too technical for me to understand. I'm looking for something that I can rely on with OpenWRT. Please LMK if I'm missing something, the thread is pretty beefy at >300 replies.
Especially with >>1 GBit/s in mind, you're quickly down to (non-Atom) x86_64, which can be a valid competitor, both on prices and idle power consumption (if chosen wisely).
Are there any specific devices you could link so that I could get a better idea of what we're talking about?