Mstn 2024 has some surfaced some iTwins Collaboration functionality as a Tech Preview.

Dual app working: One good tool to have is to enable the user to select an imodel in the iTwin viewer and download, attach the imodel to the paired Mstn session. Or if the selected imodel is in the viewers PW Drive, attach the originating dgn as a Ref attachment (or open, exchange to) in Mstn.