When choosing a UK casino with a strong slot library, pay attention to RTP...

https://varimail.com/articles/what-high-rtp-slots-can-i-find-on-mrq/

When choosing a UK casino with a strong slot library, pay attention to RTP since it reflects long-term returns. Some slots offer different RTP versions depending on the operator, so it's worth comparing sites like Casumo, bet365 Casino, and Party Casino