have you had a good look at the top? over time the top can bugle around the bridge from string tension, also check if the bridge is lift off at all, both those things are common on old acoustics and will raise action and could also be down to a split or delaminated brace. You should take the strings off for a few days and see what the straightness of the neck is like, You could also see what happens when you go down a gauge or two, switch down from 12 or 13 to 10 or 11 is a big reduction in tension and thus height of the bridge relative to the fretboard.
You could totally remove the fretboard and plane out a bit of the relief in the neck, I would be up for routing a truss rod channel too, that would definitely help to future proof it but you'd probably need to get the neck fairly flat before hand. The other common thing which I haven't had to do yet is a neck reset which usually involves shaving a bit off the bottom of the heel and shimming under the fretboard, providing you can safely remove it.
I recommend checking out Ted Woodford on youtube, that dude is a wizard. https://www.youtube.com/@twoodfrd