Keep pinch-puncturing my rear Crossmark (2.1″ plain folding).

Leaving tubeless conversion, LUST versions and not ploughing through rock gardens like an idiot aside for a moment, would the larger 2.25″ versions of the same tyre be any more resistant?

(rationale: I might try tubeless but not straight away)

OR any other similar performing tyres you’d recommend? Saguaro TNT (although can’t find any cheap)? Onza Canis? Specialized Captain Control? Basically a fast rolling tyre that stands up to abuse.

What pressure are you running? Sounds like it might be a little low if you keep doing it..
You could try the EXO sidewalled Maxxis as they are protected on the sidewalls and have a bit more strength

Have been running between 25-30psi according to the track pump gauge. Now upped to 35 but quite liked the grip the lower pressure gave. Guess I need to lump it for a while and then make the effort to go tubeless.

Pinching = too low a pressure.
Its always a compromise between traction and pinch resistance.
Tubeless does away with that particular compromise, but introduces a whole new level of faff, expense and hassle.