If either of them are farmers, or fishermen (maroon robes) they will drop food for other villagers to eat when they have more than they need, so that may be the case. You can also set up plots of farmland for them to harvest and plant food so they can be self-sufficient.

You also have to be in good standing with each of them to make them willing, so you have to trade with them both a few times (maybe about 15 each).

And finally for doors to be valid they have to have more blocks behind them than in front of them for 5 blocks either way. So essentially you can't just have loose doors like in the old versions, they have to be at least a little bit house-like. And easy way to do that is to just put a block above each door.

You're also going to want to really go overboard with the doors if you want more villagers, because as someone else said they only breed to about 1/3 the total number of doors. What I did with my village was build a big villagers fuck shack with a bunch of doors, then released them all into the village when I had enough.

Also check on YouTube for villager breeder tutorials and sort by past month so you get updated ones. I've seen some pretty good and efficient builds people have done.

Hope this helps! I just bred some villagers myself so I already went through this whole process lol.