There are CB door jamb mounts. For example the Firestick MK204R, but zip for 2M/440 antennas.
You could use the Firestick mount and substitute an NMO base for the 3/8 threaded one that's there.
Does anyone make a door jamb antenna for 2M/440 antennas? Seems not to be.
It's not that common. The closest thing I've seen is right angle NMO fender mounts (which you could attach to the referenced Firestick mount).
Does it have to be this hard?
What you're doing is a custom install, so you're going to have to roll it yourself. Sometimes you get lucky and all the bits are exactly what you need but when they're not, you have to mix and match or fabricate yourself
What's wrong with just putting it on the roof?
Mark K5LXP
Albuquerque, NM