If they're designed to run with a standard air flow, just not the airflow behind your television or inside your TV stand.
Why not include a fan that only activates when it gets like 90°, that way it only turns on when you can't hear it.
And it tells you when it's super hot, and maybe a fan light, so you can consider moving it.
I mean these modem router combos will last more than a decade it taken care of.
Also if you got any free streaming services, everything from free Hulu sites, to anime sites, I'm collecting a bunch of them so feel free and share.