South Wales and Forest of Dean is rammed with primo riding; you can mix and match between pedaling and uplifted days, with plenty of civilization and culture nearby.
Hard to list all available venues; Besides the obvious uplifted venues: Bike Park Wales, Dirt Farm and the soon to be open Hafod Bike Park, there’s trails scattered everywhere in a wide range of flavours; here is just a few
Cwmcarn (Risca)
Barry Sidings
Tirpentwys Trails
Machen
Afan
As for Forest of Dean, besides the cycle centre itself (which is well worth a visit), there is a wealth of sublime off piste
Between the 2, there’s more than enough for a week’s riding with plenty of variety; 2 weeks and you could venture more northward for the delights of Dyfi, Gwydir etc etc
Pound for pound, I honestly think Wales is among the best in the world right now for trails that don’t require uplifting, whilst also offering plenty of uplift venues on top.