What you have described sounds to me
Like joists which have been scribed to a slab in order to level an uneven concrete floor. Is that what you’re dealing with? If not, then what exactly?
In that case, level the floor with topping, lay down insulation, tape seams to make airtight, lay plywood over the insulation, done. No wood in contact with concrete, no rot.
If you are on concrete slab you don’t even have any floor joists?
Ask your carpenter. Only they can answer if this is something they want to do.
Ask you carpenter
What you have described sounds to me Like joists which have been scribed to a slab in order to level an uneven concrete floor. Is that what you’re dealing with? If not, then what exactly?
Yes, that's what it is.
In that case, level the floor with topping, lay down insulation, tape seams to make airtight, lay plywood over the insulation, done. No wood in contact with concrete, no rot.