There are some decent decaffs these days. In my local Tesco the best bet is Taylor’s.
If I want to splash out, I’d get something from one of these places –
https://www.decadentdecaf.com/collections/decaf-coffee-range
https://jamesgourmetcoffee.com/filter-profile-coffee/
…which I do occasionally, but either you buy one pack and it costs you a tenner delivered, which seems like an awful lot, or try to spread the delivery charge by buying several packs, and you end up spending £35 on coffee in one go, which also seems like an awful lot.