The garage floor in my home is pitted and has undulations in the
finish. The inspector thought that the original slab might have been
pitted or damaged by the rain and they attempted to lay a thin layer
over it to "fix" the problem -- and now that layer has come off in
places. There does not seem to be any new pieces coming off.

What (if any) would be a good product to even the floor with? I would
like to smooth it to the point I could successfully apply a floor
sealer that you come across in automotive shops - the one that achieves
that grey, smooth appearance.

I would also be interested in tips, best practices, etc. as they relate
to the project as a whole.

Thanks in advance!

Ian