Transporters essentially destroy and recreate people anyway, you have to imagine it is already something that most folks in Starfleet have made peace with, somehow.

Tom Riker is proof that we’re just bags of meat, and consciousness is an emergent phenomenon. The only difference is that instances copies have a divergence point in their experiences. The Bobiverse books explore similar ideas.

But it is hard to imagine those instances wouldn’t want to avoid getting merc’d Tuvix-style. The handwavium way you’d probably try to approach it would be some sort of memory reintegration. Not implausible in Star Trek