One of the most flexible options out there, MPC is not limited to a specific network by a smart contract, but it does require trust in potentially opaque partners. MPC is closer to the base layer of crypto, the private key entropy, and all the participants in an MPC wallet participate together to recreate the private key, instead of having multiple private keys send their own valid signatures. There’s Qredo and Lit protocols for those who are more technically savvy, which are fully decentralized solutions, but for advisors that want a little more white glove treatment and are willing to work with trusted third parties, Anchorage just released their enterprise solution, Porto, and my own company Hedgehog just released an MPC account management product with a focus on fund administration, sub-advisory, and turnkey asset management programs.