Cashapp itself is custodial, like any exchange. You have to withdraw to another wallet for self custody. Personally I prefer my custodial and non custodial wallets as seperate apps. Never tried peach, but have heard good things.
Discussion
Few exceptions, p2p exchanges are non custodial you trade directly with a peer. Bull Bitcoin is not custodial similar as peer to peer but is KYCd but you have to put in a receiving address when you buy so they never hold your bitcoin for you.