A UKGC licence is the starting point, not a guarantee of a smooth experience....

https://www.bookmarking-maze.win/a-ukgc-licence-is-the-baseline-not-a-quality-stamp-check-published-rtps

A UKGC licence is the starting point, not a guarantee of a smooth experience. Check whether a site clearly lists slot RTPs, explains how long withdrawals usually take, and offers practical responsible gambling tools such as deposit limits and time-outs