Can I restore my wiped out Religion in Civ 6?

I was late to the religion party, so my neighbour snuck in and converted all my cities to his religion. Now I seem to be unable get my own religion back.

In the previous edition, I could use a Great Prophet, or just rely on my Holy City's strong pressure, but neither of these options seems to be available in Civ 6 (I have no Great Prophets available under Great People, it seems like they are only used to found a religion now?).

I have thousands of stored faith, but any unit I buy will have the dominant religion (my neighbour's).

I've tried looking through the civilopedia, to no avail.

Has anyone found a way of clawing back your own religion from destruction?

I believe you have lost the religious war, friend.

You are correct about Great Prophets; there are indeed a limited quantity of them. In my 6-player game on Prince difficulty, there were 4 Great Prophets. I believe you are also correct in saying they are used strictly for founding a Religion. I did not notice any other options for that unit during my game.

As you have mentioned, buying units with faith corresponds to the dominant religion in that city. If you still have citizens following your religion, there may be some small hope for the pressure to bubble and your religion to become dominant again, but that is unlikely at best. Cities spread pressure based on how many followers are in that city; the dominant religion will almost always be emitting the most pressure. If you chose traits that increase pressure in some way, your religion might resurface. Otherwise, I believe it has been lost to the waves of time.

DISCLAIMER: This game is a new release, and this evidence is almost all anecdotal from gameplay experience.

You actually might still have a chance. Killing religious units reduces that religion in a radius by up to 250. So just declare war on who ever is the majority and run over all the missionaries and apostles with horseman.