Amps In terms of buying currency or NFTs?
For currency it appears Binance are back in the game after complying will all of the stipulations from the FCA, so for absolute choice I would go there.
Other exchanges include Coinbase, KuCoin, crypto.com, there are literally loads of them.
If you are a big player and want to buy OTC, I can recommend GlobalBlock.co.uk based in London.