My ‘09 Subie Outback is closing in on 300k, and the previous owner did quite a bit of heavy (for an ‘09 Outback) towing with it. (I’ve only done moderate towing, and not a lot of it. The car was purchased @ just under 100k miles on it.) So far, it still has the all original power train. The transmission seems ok (except a little while back a hose clamp broke and the feed to the transmission cooler blew off. That got me a long afternoon pulled off at a little cemetery until my daughter could come get me & haul me back home for tools, a new clamp, and trans fluid.) (Subies take a unique fluid, so I keep some on hand.)
I do monitor the trans fluid (all fluids, actually) and change it out when it starts getting a little brown color in it. Plus wifey and I are not drivers who would stress a transmission badly.
Your car has a trans dipstick? How lucky you are.