>I would appreciate any input on this.

I don't think you'll get much here, because there are hundreds of routers, and many have whatever router their ISP provides - I mean if I have one modem/router (a cheap chinese ZXHN H168N V3.1 by ZTE) which does both connect to DSL/web and provide wireless LAN, then that can possibly be the case more often than one'd expect. And that's also not a piece of equipment one changes often, perhaps once in five or more years. I don't think the collective experience of a few dozen of us would tell you much.

Now after saying I don't have much to say :), a few observations, from the last dozen years with this router (and the previous model of the same). First, the distance doesn't mean much - I'm getting a much better reception in the yard, meaning some 15m away, through the metal construction of the terrace's roof, than at bare 3m upstairs, straight above the router. If it were for the rebar in the floor, that still can't explain how I get much better reception 4m away, also upstairs, with lots more of iron and concrete between the transmitter and the receiver. And, again, why are there two blind corners downstairs, bare 6m from the router, with practically no rebar along the path in that direction.

Inscrutable are the ways of electrons...
Things you may try:
- move the router, raise it closer to the ceiling
- try to keep it away from the electric cables in the wall; these may or may not interfere with the frequency your router's using
- try to upend it, i.e. sit it vertically on left or right side, so if its antenna was horizontal it now becomes vertical; even better, if it has its own antennae (am. aerial, though both words are equally wrong), try to move them around just like you once did with rabbit ears - it IS the same thing, only this time you're adjusting the sender, not the receiver.
- don't use röntgen machines around network cables (ok, this is unrelated, but had to vent my frustration from past cases, these machines are hell for networking)