The inner folding screen, outer display, dual batteries and USB-C port board each have their own repair procedures.
What to check before buying
Inner and outer screens
iFixit lists an inner-screen assembly and an outer display. Damage to the fold should not be costed as an ordinary exterior-screen replacement.
Batteries and charging
The flip and base have separate battery work, and the USB-C port sits on a documented board. These are Fold-specific assemblies.