Interesting thought.
You can't really make PVE experiences without making it custom. Verified-mode maps have restrictions. There are a bunch of 'LSFY' servers which are verified-mode and have one team that is only players and another team that is mostly bots, but there are still players on that other team because it is a verified-mode requirement. And they made the player damage real weird and the vehicle damage really weird. I don't get it. I don't understand the intent.
But, to answer your question directly, to make a true PVE conquest, it would need to be custom and someone would have to go through and manually 1:1 recreate a conquest map. Are there already images of maps that show exactly where the default spawns are, HQs, objectives, and vehicles? So someone could faithfully recreate it more easily with less research being required?
I mean, if you don't care about it actually being "default" in the exact sense of the word, making something which approximates default conquest but PVE wouldn't be too hard to make.