I bought a Flint 2 GL-MT6000 and I’ve been pretty happy with the choice.

• its currently on sale for $125
• it comes with a custom version of open-wrt, but it can be flashed to a different firmware
• easily purchaseable through their site
• I have not had signal issues in my place, but YMMV
• sustained speeds are at least 500Mb/s
• supports features like VLAN, which is part of why I bought it

Side note: Flint 3 just came out, but I’m not familiar enough with it to recommend.