edit: found this on crowdsupply but doesn't do wi-fi https://www.crowdsupply.com/search?q=Router
edit: found this on crowdsupply but doesn't do wi-fi https://www.crowdsupply.com/search?q=Router
I placed one of these boxes behind my ADSL router to do load-balancing. To use it as an Internet router, you'd instead need to couple it with a modem. A colleague whom I trust recommends Draytek kit but (a) I've not tried it, (b) it's not cheap and (c) I'm just a stranger on the Internet, so read around carefully before splashing out.
a) what your WAN connection is and b) how open you need it to be (i.e. there are no open hardware wifi cards)
My WAN port is Ethernet (the GPON conversion is done in a box I don't control). This has the advantage that pretty much any OpenWRT router will work.
I currently use a Traverse Ten64 (disclosure: received the unit for free as part of a beta test) which works reasonably well.
You could also look at gl-inet as someone else has mentioned, or the Turris range of routers. I would not be bothering with flashing a commercial router with OpenWRT anymore.