Personally, I bought a cheap fanless Chinese (Topton) router (N5105, 4xi225v3) system from AliExpress running OPNsense that's worked flawlessly for the past year or so, but I'd recommend ordering your minipcs through a vendor where you can easily return it (like Amazon) if it's DOA or otherwise doesn't meet your expectations. I'd also skip the small Chinese vendors if warranty support is something you need. Go with a manufacturer that has a local office/support.
Also, depending on what you want your server for, if you want ECC, your minipc options will be extremely limited (a couple Xeon options when I looked). Personally, I went with an desktop Ryzen + ASRock Rack mini-ITX board in a slim case that was still pretty small since I wanted ECC for ZFS.
I do wish there were one of them that included even two 3.5" drive bays so it can run as a forbidden home server doing all the things.
Intel NUC is the BMW of mini PCs, certainly not "inexpensive" compared to the alternatives, even if we ignore the off-brand stuff.
NUC and their ilk were a game changer and I'm glad to see a way for them to continue.
for who accept Chinese brands (and suspicious Windows license): Beelink, Minisforum, etc
the rest: ECS Liva or ASRock DeskMini?
Very nice little platforms with low power draw, and low noise!
I’ve got one of the DeskMini X300 on my desk atm with a 5750GE in it - 8c16t of Zen3 in 35W. It’s competitive with M1 Pro for performance and power draw.