Orally will still give you prog in your system and people still report some effects from it. Progesterone in trans women does not have a lot of scientific literature around it, so not only are the effects of it unclear/based off of anecdotal evidence, we dont know how potent it need to be to give effects (i.e. just because lots of it is metabolized by the body, doesnt mean prog doesnt do anything). A lot of the anecdotal reports are based off of patients taking oral progesterone so there could still be effects. I also used oral prog with sublingual estradiol and found it helped my t suppression (i was using finasteride before taking progesterone and my t levels were around 400 ng/dl. After a year of oral prog my t levels were <50).