The international building code has established doorknob height between 34 and 48 inches above a finished floor.
Interior door height off floor.
On the inside of the entry door finished flooring is laid on the concrete or wood sub.
The standard height of the rough opening for a door is the door height plus 2 5 8 inches.
To fix the issue the doors need to be removed bottom of the jambs cut and reset the door.
Figure 2 floor relative to entry door.
The height of common doors is 6 feet 8 inches.
The 2018 irc continues to require the bottom of openings created by operable windows to be a minimum height of 24 inches above the adjacent interior floor when they are more than 6 feet above the grade outside the window.
Interior door height off floor.
The additional room allows for a 3 4 inch top jamb a shim.
The standard i use is 1 2 over finish floors 3 4 is acceptable.
That is a lot of room for unlevel you have there.
I just took a quick look at some of standards and regulations governing door undercut which is the distance between a door and finished floor as opposed to clearance which is door to sub floor.
The awi gives no minimum but a maximum of over 3 4 is unacceptable.