Its worth looking at
https://history.nasa.gov/SP-4218/ch4.htm which covers the earlier history of the Arecibo dish.
The only comparable dish for long range deep space radar is in southern China:
https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_TelescopeIts only been online since 2017 and wasn't fully operational till the beginning of this year. We are lucky not to have had a critical gap in Earth's planetary radar capabilty.
Can the Western world really afford to leave accurate orbit characterization of Earth crossing asteroid threats to the Chinese? There aren't that many near equatorial suitable sites in countries that are firmly under Western world control, so IMHO rebuilding at Arecebo is well worth considering - its already got most of the ancillary infrastructure required and a prepared depression that just needs the scrap cleared out.
The dish was originally wire mesh (literally chicken wire) and was upgraded to aluminum panels in the early '70s to extend its capability to S band operation. A wire mesh dish (or partially wire mesh with a high quality aluminum reflector in the center, elongated on its north-south axis) might be a cheap way of getting reasonable capability back into operation on the site. Its possible that significant areas of the reflector panels could be salvaged safely for reuse.
The Arecibo feed platform needed to be as massive as it was because it was built with 1960's technology. Modern composites would permit a much lighter structure, and modern electronics would permit a significantly smaller structure, so it could reasonably be lowered onto composite pylons protruding through the reflector to 'dock' it for maintenance and to withstand hurricanes. Initially it could be lofted by a commercially available tower crane with its base located in the eastern or western quadrants of the reflector. As funds allow, it could be upgraded to a suspension system similar to the previous one, but built with corrosion resistant materials.