went there early in 2022. Using UMobile no issues at GPO, First World, and even Sky Avenue. Good 4G signal and comparing my friend who is on Maxis and Celcom 4G signal sometimes 2 bar vs UMobile full where sitting in the same restaurant.

But UMobile may not be so good during the route to Genting highlands..though as their 4G coverage is still not as widely spread as Maxis/Celcom.