BCH has "instant" finality in that there's no replace by fee, so transactions can be trusted with 0 confirmations. There are trade offs here and I'm not exactly a fan of it but it is one way to do it.

The issue of finality is a very complex one. Technically no blockchain has 100% finality ever. Practically speaking, finality is a bell curve and depending on network security practical finality is possible after a handful of blocks. In XMR that's deemed to be 10 blocks as of right now. This is true regardless of proof of work or proof of stake and is a fundamental problem of achieving consensus in a decentralized way. Proof of stake could actually reduce the security of finality, because it rewards holders and not external expenditure, and so trends towards oligarchic centralization enabling a small number of nodes to potentially collude to break finality to their benefit. If staking nodes decide to do this there's no way to fork away from them, as they will have the same number of coins on the fork and so will be able to continue the attack, as opposed to PoW where you can bit flip the hash algorithm and thus boot the attackers permanently.