It's similar in that 8k sigs are collected and coalesced to sign something. From there the differences begin. M-of-N schemes must be orchestrated ahead of time, using Shamir's or by constructing a BTC multisig UTXO or something. When signing, one may choose freely among the key shards. It's performed in the usual execution layer of the chain.

Whereas in ETH PoS, validation happens in the consensus layer, following strict self-imposed rules. With each new block, one validator is chosen to propose the block, and thousands of validators are asked to back the proposer. The proposer and attestors are chosen randomly but specifically with no freedom to mix and match; the chosen validators must attest (and receive a reward) or else be penalized. Validators don't know each other and they don't need to cooperate to create a shared key ahead of time, all they have to do is deposit and follow the rules. The signatures are agglomerated by [BLS ellipical curve stuff idk it's magic] and help to form the consensus chain itself.