Opill is known as a “mini pill” because it contains only one hormone, progestin, in contrast to “combination” pills, which contain both progestin and estrogen. A company that makes a combination pill, Cadence Health, has also been in discussions with the F.D.A. about applying for over-the-counter status.
So good luck DIYing a transition with these. Progesterone will develop milk ducts but it won't make breasts grow.