I have read somewhere what you can pure inside leadscrew some material
like moglice and fix the backlash plus this material has lower friction than bronze nut.
I have done moglice nuts and they work surprisingly well if the screw is not worn too much. Ball screw is a better option in general.
If you want to go the moglice route, I would check with your supplier on pricing. It's not cheap. It's a system (type for nut/bearing FLP, I think it was) and you need to get the release wax they recommend and lapping compound that does not imbed. Timesaver yellow is what I used.
The process in a nutshell is to bore out the old nut, place it on the least worn section of prepared/waxed screw, fix it radially concentric to screw, seal and cap the openings and fill with moglice through a low point fill port. You'll need a vent and dam at the high point to capture excess resin. You want to fill it with minimal chance of trapping air. Make sure there are no leaks as the resin takes some time to gel and it can run out of the nut housing if you're not careful. When set, you have to break it free from the threads which should work okay if screw was waxed. Final lapping in place will get it to the feel you want.
