I have my Dish phone locked to NR-only. That keeps it on Dish and only occasionally will it see T-Mobile NR SA for brief periods before going to no service.
I also don't have mine band locked beyond that, except that I have some of the unused bands turned off just to try to reduce scan time. Fortunately, my Dish phone is the one with the MediaTek chipset, so it has NR neighbor cells, and I can usually see n71, n70, n66, and sometimes n29 (market-dependent) through those regardless of which band it's connected to as primary.
- Trip