L2 solutions for them seem like a duct tape solution, and i am way out of my depth by the legal complexity of the whole issue, but what i am aware is that both chains lack the level of privacy that GDPR would need. And AML laws alone are complex for any permissionless transactions without L1 build in KYC.
What ever platform they choose in the end, it will most likely look very different from the current cryptos out there. And i would be surprised if incentives for protecting the chain (coins) would have cheap and fast transactions. Protecting privacy, integrity, and stability of chain worth trillions of dollars will cost some serious money.
I am also fairly certain that they won't use centralized system in the end, as no country out there would trust that one centralized entity enough.
I've seen stablecoins with a "blacklist" feature "baked" into the code. If they can do that, it'll be easy enough to make a regulatory-compliant digital currency on a public blockchain network. The real problem would be obfuscating sensitive transactions. Especially on transparent ledgers such as Ethereum and XRP. ZKPs (Zero Knowledge Proofs) provide the solution to this, but I doubt the XRP developer team are going to integrate it. It makes more sense to develop a private blockchain network where central banks like the FED and ECB have full control over it. Existing stablecoins could be "bridged" to such chain if governments want to.
Whenever Ripple's stablecoin, Tether's USDT, or Circle's USDC will be the next US Digital Dollar, you can be certain that paper money's days are coming to an end. The world will be fully digitized, giving governments more control over our lives. We won't truly own anything. I sure hope BTC stays alive by the time CBDCs rule the world. Otherwise, it will be the end of privacy and freedom for good.