Your best bet would be to call the manufacturer of the new product and ask if their product can be installed over preexisting wood floor without voiding any warranties.

I dont think your installers will warranty that kind of work. Too many problems can happen.

I'd try pulling some up. I recently replaced some glued wood that had been down for 6 years. Glue was hardly holding and the residue on the subfloor scraped off easily.

If it was glued properly, it won't come apart from the plywood. It is like trying to separate the plies in plywood. You will pull chunks of plywood up with the flooring. You have two options. 1. replace the flooring and plywood. 2. Consider the flooring as part of the sub-floor and install on top of it. If you are gluing an engineered floor down, you will need to sand the existing floor to open the grain. Adhesives won't bond to the surface of a finished floor. Engineered flooring is no different than plywood. I have never seen any manufacturer's warranties that were nullified by installing over existing flooring. I sell flooring, and am really familiar with the warranty restrictions of most major brands.

Mirage Flooring

Go for it. Glue and nail. Or just nail. But have you considered refinishing those old floors. Some lace in can be done if needed and a full sand and finish for a lot less money while preserving some history is kind fun and maybe a bit nicer than bamboo. Look at Rubio Monocoat “fume” and “pure”