if it's only a maxed trussrod, it's an easy and common fix to restore adjustability ...
- remove the neck (assuming this is a heel adjust neck)
- loosen the trussrod adjustment nut until it comes off
- lubricate the trussrod threads (rod and nut)
- install several flat washers that have an inner diameter that fits over the trussrod and an outer diameter that fits down into the hole (these are available if you know where to look)
- reinstall the trussrod nut
- reinstall the neck
- adjust the trussrod to perfection (if you need more adjustment, follow the process to add a couple more washers)
this fix had been performend on thousands upon thousands of necks the past decades - your neck may have this fix and you may not even know it
the usual reason that a trussrod maxes out is that you reach the end of cut threads (or length inside the nut) before finding the amout of relief you're shooting for. this usually happens because the nut rests directly on the wood, and over time this wood compresses resulting in less adjustment travel before bottoming out. the washers serve to compensate for this compression and restore the amount of threads available for adjusting the nut. adding these washers is not modifying the neck in any way when executed properly
all the best,
R