Sync for Smart Collections

Two plugins allow you to sync smart collections from LR Classic to LR Cloud, Any Source and Smart-Collection Sync.  They both work the same way -- they sync from the smart collection to a dumb collection within LR, and you enable cloud-sync on the dumb collection.

Adobe never comments on future developments, but in this case it is safe to say that the answer will be negative. When Lightroom desktop was introduced, Adobe made it clear that Lightroom Classic would not get any new syncing functionality anymore.