No. HNWI need self-custody wallets that are open source, properly reviewed and tested with multi-sig (probably MPC with FROST going forward) to avoid single points of failure that are easy and intuitive to use. Having vaults would probably also be desirable for added security.

A bespoke, one-off wallet sounds like sth that is neither open source nor properly reviewed. Smart people wouldn't put their money in sth that is experimental and not properly tested or reviewed. Most OGs probably still use Electrum because it's been around for so long.