Resin drive covering is nothing but a bodge unless the whole substrate is sound.
The only way to guarantee this is to dig up the existing drive, lay down a good depth of hardcore (properly laid and vibrated down).
If it was me I would get a decent builder to relay the drive properly - where I walk the dogs there are a couple of examples that look pants (there is a big radio ad on local FM for a company near me and I have yet to se something I would be happy with).
Others may have a different experience but for me it's a bodge.