Usually when we installing doors we put pieces of flooring that will be used under the jamb so the flooring guys don't have to undercut the jambs.

I wouldn't be replacing jambs at this point, if anything get him pieces of flooring that will be going in, slip them under the door and raise the doors.

Another way is to cut the doors and the flooring guys will undercut the jambs to slip the flooring under it.

Good luck

If the jambs can't be easily raised, undercut the doors and let the flooring installers undercut the jambs.

I undercut doors as little as possible as there are other ways to provide for return air.

Never had to undercut doors. I always frame my openings 83". If carpet goes in, I raise the door 1/2" so the carpet can be tucked under it and if pre- finished hardwood flooring goes in I set the doors on scraps of that flooring. It makes a nicer job and a perfect tight fit every time.

If unfinished flooring, they install flooring before I set doors.

When you start undercutting the jambs not always you get precise cuts and at times it looks messy, the cuts not so clean, and you end up with gaps here and there.

Never had to undercut doors. I always frame my openings 83".

Yes, but the OP has 12 installed jambs that don't provide clearance for the floors and that may not be easily removed. We're not on site to check that.

When you start undercutting the jambs not always you get precise cuts
and at times it looks messy, the cuts not so clean, and you end up with
gaps here and there.

It all depends on the floor installers. A couple of homes ago I ended up correcting some of those sloppy cuts myself with a handheld undercut saw.

Of course, if the OP has not paid the carpenter, then she's in control.Time for an executive decision!

Unless you provided specific instruction, this is typical for your finish carpenter.