Twice a week is plenty for PT. So is once a week.
My surgeon doesn't allow any formal PT at all for the first month after surgery. He says that your knee needs that time, to start on its journey of healing.
After a month, he allows PT, but only once every two weeks. At the PT session, no one pushes on our knees or expects a lot of work. We are just shown a few, new exercises. In between visits, we do a few of those exercises by ourselves, at home.
His patients all do well and he hasn't had to do an MUA to help with ROM for the last 4 years.
It's not exercising that gets you your ROM, it's time. Time to recover, time for swelling and pain to settle and time to heal. Your ROM is there right from the start, just waiting for all that to happen so it can show itself.