I have a bedroom Roku TV made by Hisense that we bought several years ago. The S/N is 2N0009822083 with a software version of 11.0.0 build 4193-11
Our second is in the living room is made by Onn and we bought it a few months ago. The S/N is X0000CJK5KJ with a software version of 11.0.0 build 4193-DF
From the very first day use of the remote for new ROKU TV often turns on or changes things on the older one. There is no line of sight between the two if you're thinking the older TV gets IR from the newer one. I don't think so since the door is often closed and the problem still happens.
Please restore our sanity.
IR signal can balance off walls, if it were wifi signal which goes through walls it can't be pa I red to more then one Roku at a time. Your Hisense and Onn Roku tv' s remote emit different codes, but yge problem here is that the Hisense accepts both codes, where Onn only accepts one.
You could purchase a voice remote, which the wifi remote would be paired to the Onn Roku tv, so wifi remote will only control the Onn, and Hisense remote would only control the Hisense. You would have to abandon the Onn Ir remote for good.