@Stacy-And-John0 As long as the listing is explicit about the fact that the hot tub is shared with other guests, it shouldn't be a problem.
I guess you could use Covid safety as a pretext for designating separate "hot tub hours" for each listing so they each get a private time block. But you could also let people feel free to make their own decisions about whether they feel like sharing the tub with strangers. One way or other, they're stewing in each other's bodily secretions anyway, so it's not exactly "private."