I try to avoid new slots on Nolimit Relax and special slots with Xtra bets (UKGC should ban all Xtra bets) I think they just trying to milk are pocket to the max, I stick with Novo PNG Blueprint Microgaming Netent Merkur Push Gaming, is new provider called Gamomat they have good slots but not many UK casino has this provider
But the worst slots for me are BTG slots
I find BTG slots pretty good generally except gold and that infinity spins one those two are worth avoiding
You mentioned not being able to bonus Gold by BTG. It’s one of their earlier slots, around 2013 or 2014 and it’s a typical 5×3 affair. From what I can remember, the feature is 12 or 15 free spins with all wins x 3, so very much like Lady Lady’s Charm (Astra / Novomatic) or Madame Destiny (Pragmatic).