Question for the watchmakers out there...

It all depends on how badly damaged it is, I guess. You're right, you can try to take a shortened tap and go through the thread again. But if it is bad, it might be difficult to find the start of the thread and force your way through.

Depending on how much solid material the crown has, it might be possible to drill it out and insert a new tube. But you will need a pretty enthusiastic watchmaker to attempt that... 😲

There are always ways to repair things, some better than others. Unless it is really hard to find a functional part for a good price, I would avoid this crown and wait for a good one.

If you can get the stem in the crown, you might try Loctite 660 retaining compound.

I had a cheap diaphragm compressor where the motor bearing at the crank end began to slip on the shaft and wore a groove in the shaft. Between a metal shim and this stuff, I got several more years from the compressor before replacing it.

They also make PC 3967 thread repair compound which touts the ability to replace worn threads with new "metal" and still have a functional threaded joint. Can't vouch for it.

The sales blurb for 660 says "LOCTITE 660 is a high strength retaining compound with good gap filling properties, ideal for repairing worn-out seats, keys, splines, bearings or tapers without remachining." That's pretty confident, but in line with my experience.