To control only one Roku at a time, the Roku's, all of them, has to have wifi remotes. Any of them with IR remotes will control all Roku in line of sight of the IR remote. If the TVs are all them same brand, no Roku remotes will differentiate the tv commands from each other.
To expand on Tivoburkee's post a bit.
If you buy ROKU TVs, i.e. TVs with Roku functionality built in, they all come from their various manufacturers with direct line of sight infrared (IR) remotes, using the same set of IR commands (with one minor exception I won't bother you with here). So, as Tivoburkee said, each of those original equipment remotes will control ALL of the sets its signal reaches (and sometimes it's surprising how much an IR signal can bounce around and reach a set you're not actually pointing at).
If you instead buy separate Roku players and connect them to non-Roku TVs, the same situation exists for any Roku models that accept IR commands. In the current line, this is all models except the two Streaming Stick models (they are usually installed behind the TV where IR can't reach so they don't even have IR receptors and so can only be controlled by wifi remotes). IR-equipped Roku players all use a common set of IR commands, although it is a different set than the Roku TVs use, so again any IR remote for a Roku player can control all other IR-equipped Roku players if the players are placed where the IR signal can reach them.
So the solution is to use wifi remotes, i.e. the Roku "Voice Remote" models. Each Voice Remote is paired to the Roku it is meant to control, and once paired will only work with that Roku. That means each Roku will need its own Voice Remote. All current Rokus (TVs and players) can be controlled by Roku Voice Remotes, although not all players come with them.
All current Roku players are supplied with Voice Remotes, with the exception of the two lowest tier players, the Express and Express 4K (models 3930 & 3940), which come with simple IR remotes. So for those two models and any Roku TVs, you'd need to purchase additional Voice Remotes and hide their IR remotes away somewhere.
So if I have two Roku sticks in the same room can I control each separately from the Roku app?
Yeah, I never noticed it before, but I opened a roku app on my phone and when I chose "switch device" it shows 3 Roku Ultras that I can control.
I also use 2 Roku remotes on the same table in the living room; each controls a different Ultra, and the TV switches inputs according to what remote I grab.
So you can control each individually with multiple remotes, or use the app and choose which it controls (each Roku has a name and a location (e.g. Roku 1, Living Room), and that's what I see in the app). Proximity is no problem. Just choose a model that uses a wifi-direct remote.
That would be great but I can't get the app to connect to my Roku stick. I've tried everything including entering the IP address of the Roku to connect manually. I need to operate two in the same room to stream sports on two different sticks but I'm not going to buy second stick unless I can get the first to connect. It's really dumb that you can't just pair the remote to only one stick.
