> I recently upgraded from a UniFi Dream Machine to a UniFi Dream Router 7

What do these devices do that can't be accomplished by an OpenWrt One + an external AP for less money and fully FOSS?

Another option would be a mini-PC running Linux, but it's perhaps overkill for a domestic router.

Edit: Actually the OpenWrt One does have built-in WiFi, so you don't even need the external AP.