The Minisforum, Beelink and the generic aliexpress units are incredibly cheap.
There are celeron based fanless models with 4 2.5gbe NICs available for less than $200 on Amazon.
Personally I have been using the AMD 15w Ryzen variants it’s a nice balance for performance. I have several, my daily driver is an Asus PN50 with 2Tb nvme disk and 64GB ram driving 3 sceeens at 2560x1440 in a completely silent Akasa case.
As long as you are prepared to fiddle and potentially destroy the original case rhe Akasa cases are fantastic.