I think there was a thread somewhere about someone who inherited a frame from his father that was too large for him, had it disassembled and rebuilt for nostalgia. But doing so is rare.

In your case, if you are wanting to simply cut off the TT/DT and move the HT, that should be simple enough, but that will also lower the point of the bottom of the head tube. Thus, the frame will sit higher on the fork, and could potentially throw off all the other angles on the frame.

You could change the angle of the DT at the bottom bracket, but then you'll also be dealing with tire clearance issues which may or may not be an issue.

Going to a smaller front wheel like was done with some Terry and a few other vintage women's bikes would be an option to recover the original geometry with a shorter fork.

Before making the change, I'd carefully consider whether you can make adequate adjustments by going with a shorter stem, if reach is the only issue.

Perhaps get a "fitting" done to confirm your goal of a shorter reach.

Then start scouring frames for one with the dimensions that you wish.

One of the oddest short frames is the Gitane Traveler (or traveller). But, that frame also used a very long stem, and perhaps a few other optimizations to make up for the short length.

If this is all simply a frame size issue, many used frames are cheap.