Solarpunk technology

A few remarks from your friendly neighbor open hardware preacher:

• Magnet-less techs do exist, and do not need to be found in 19th century designs, which are usually very energy-inefficient. Modern knowledge of magnetic leakage, more efficient electronic drivers make these designs usually a bad idea.
• Open source hardware motors are a thing
• The crucial part in making good motors without using too much labor is actually in the coil winding machine that goes with it. Here again, open hardware is in business.
• Rare earth are badly named. They are not rare and most of them are usually a byproduct of the refinement of other minerals.
• The USGS published yearly reports on minerals, their production, reserves and strategic importance. Here is the 2023 one on rare earths
• China produces a lot of them only because it has cheaper labor, US and other countries have tons of reserve.
• Iron magnets are easy to make (heat iron and let it cold inside a magnetic field). I believe that rare earth magnets are basically the same with an alloy with a different Curie temperature.

Any power plant operating today uses electric magnets in their generators. So this is not an issue, as long as there is a way to power the electromagnets when turning on the plant.

If we were starting from scratch, iron is about as common as it gets, geologically, not to mention how much "leftover" iron and steel there would be, post collapse. Barium/strontium for sintering ferromagnets is trickier, but ores like witherite and baryte aren't uncommon, though they are quite location specific, globally speaking. Not that you don't actually need full blown permanent magnets, just ferromagnetic material.

However, the easier (though less efficient) option would be to use dynamos with field coils instead of ferromagnets. That way the only resource you need is wire.

which is more difficult to obtain, iron based materials for permanent magnets, copper for field coils?