My stay was also in 2019 (May) and the lounge was not hidden at all to me (I knew there was one before coming but I don't remember any reluctance or problem). I indeed had breakfast in the lounge, but I am sure it was also possible to have it for free at the main restaurant. I had a very good stay in this hotel and will be very happy to return.
I made a review in the dedicated thread (post #50)
Pullman Tokyo Tamachi