I have one Roku Express and 2 Ultras. RealChoice is the app I use (no other choice) for local/live TV. I recently moved to another apt across the hall (same bldg).
On the Express, since the move, almost constant buffering on RealChoice, but not on the Ultras.
On the Express, other apps (Paramount+ and discovery+) only buffer occasionally - but haven't since moving.
One note - once before, the RealChoice tech "support" had me delete the app and I had a miserable time trying to reinstall it, so if there's some other option, I'd love to know.
Thanks.