>>2056719you've outlined the two options you have already.
if it was me I'd rebuild the wheel but I know how to build wheels. if you don't, then it kind of depends on how handy you are and how patient you are, it's a science but also a craft.
transferring everything over to another frame is a bigger job but mostly pretty straightforward. although you will have to adjust the brakes and derailleurs which is a bit specialized, and if you're using traditional headset and BB with loose bearings, the adjustment is pretty finicky but you can get sealed bearings nowadays and there's no guarantee that the new frame would fit your existing ones anyway.
the path of least resistance would be to find a shop with reasonable prices and have them build your IGH into your old rim. it'll require new spokes and iunno if they'd be willing to reuse the existing nipples assuming they're in good shape to begin with. paying for another frame and paying for the transfer would probably cost a lot more. if you diy it's a preference, but if you're paying, the wheel build won't be cheap but I've got to imagine a full transfer would be really expensive.
otoh, maybe you'd prefer 700c to 650a in which case switch the frame if you can diy. this is a personal preference so try borrowing a 700c bike if you aren't familiar. not sure there's much of a difference but these things matter to some people, particularly for esoteric use cases.
