Good UK sites: UKGC is the baseline. Clear RTPs set expectations. Check payout...

https://quebeck-wiki.win/index.php/What_Does_%E2%80%9CIndependent_Testing%E2%80%9D_Mean_for_Slot_Fairness%3F

Good UK sites: UKGC is the baseline. Clear RTPs set expectations. Check payout times and delays. Seek simple safer gambling tools: limits, time-outs, self-exclusion