When I think about unpowered speakers I think of banana plugs - not RCA. What kind of wire are you running?

I don't have a system, just trying to plan ahead. Yes, I agree banana plugs. RCA is for line level. I see something like this;

Fosmon 3-Gang 7.2 Surround Sound Distribution Wall Plate

Most of the Youtube videos I can dig up they are hard wiring speakers into the wall and ceiling. I'm looking for a bit more flexibility, but still being wired and not wireless.

I think.

Is something like that a reasonable idea?

If you are using powered speakers, then you are probably right. Of course, you would have to have a receptacle installed for each speaker. Most likely, you would be using unpowered speakers, which would have banana jacks (or no jacks, just wires coming out of the wall plate with plugs to match your speakers - most likely banana plugs). For the fronts (L/C/R), you probably wouldn't do any special wiring, unless your amp is not near your speakers and display.

Pre-wiring for a home theater is not extremely difficult, but one does need to be educated regarding the hardware and you should have a plan to work with before jumping in with the physical wiring, etc. Read through various 'how to' sites and learn the details of the hardware before going at it. I used this site's design software to locate my front and side speakers locations based on my room size and seating locations:

https://www.audioadvice.com/home-theater-design

We will have 3 front speakers (L, Ctr, & R) and 4 ceiling speakers (mid L & R, and Rear L & R) and a sub-woofer (L Ctr), all are pre-mounted to be behind drywall with only the grills showing once complete. RCA plugs are mainly relegated to signal-level applications with amplified power typically using binding posts. My theater will have an electronics closet behind it with the digital receiver, DVD player and amplifiers there on shelving. If needed, I will use an infrared repeater system to communicate from the family room with the hidden electronics. The electronics will connect to the speakers through the On-Q connection box below. Ceiling and wall speakers have their own (hidden) insulated plywood enclosure, so speaker connections are the mfr binding posts on each unit as well. Wall mount speaker binding post connections are available if you go that route.