That’s like my 3rd floor. I have all of my HDMI inputs plugged into my Yamaha receiver and it does sound for everything and the TV only has one HDMI cable in it and you switch inputs on the receiver. My boys aren’t good with the Harmony remote so they forget to put it on the charger, etc. so most times they use the stereo receiver and either the Firestick remote or the PS4 controller. It’s like an adventure every time I go up there trying to find remotes. All other TVs are just the Firestick remote.
I used to run it all through a receiver like you, but I got rid of it when I reconfigured everything. It was older and I didn't like the speakers/wire running through my living room. I had bought a sound bar, but it was clashing with the receiver - receiver kept trying to send sound to the non-existent speakers instead of the sound bar. Instead of buying another receiver, we just ran everything to the TV, but it only had 3 inputs for 4 items, so I took the chromecast out of active duty.
All of that is only for my living room TV. The rest are just Roku remote-only. I live by myself, so don't have the remote issues you do with your kids. I love that Harmony remote, though.
One thing that's weird with the sound bar (it's a Bose) is that, if I go direct to Roku, I sometimes get no sound. It powers up and is not on mute, but no sound. If I then switch to the DVD player, the sound works. Then back to Roku afterwards, the sound works - every time. It probably happens like that 2 out of every 5 times I power up. I'm sure I must have fat-fingered something somewhere along the line - I'll get my friend to look at it next time he's around.
Back to the main subject of this thread, here's my current viewing cost:
Internet - $80/month. I'd have this no matter what.
Prime - $10/month(?) and I'd have that anyway.
Locast.org for the DC local channels - $5/month. I'm in the mountains of western VA and an antenna won't do it here. I get like 30 channels.
Frndly TV - $8/month so I can get the Weather Channel
PBS Passport - $6/month. Gives me more on-demand stuff than I could possibly watch. Plus, my zip code gives me a different live stream of PBS than I get on locast.org.
That's it. I don't get ESPN, NFLN, HBO, HGTV, TNT, any of those. And I don't miss them. For live sports, I watch whatever the networks show. But, again, I'm by myself and don't have a family here with diverse viewing wishes.