We actually sell a lot of Coretec PLUS XL - the 9" textured planks. The product is 100% waterproof and looks great! All my customers love it. Cork is naturally waterproof and is the perfect piece to be attached under these floors. The locking system is also really tight so unless you got flooded from a water line breaking ( which would ruin ANY floor ) there should be no issue with spills. We have it on the floor of our showroom and its doing great! Definitely check into the flooring forum for more opinions...

Look at COREtec Wood: https://coretecfloors.com/en-us/products/coretec-wood Unlike their other lines, the top layer of this is actually wood. “Enjoy the natural grown beauty of hardwoods with the engineered resilience of COREtec. The hand formed mineral core gives you protection against exposure to moisture that will damage any other wood floor. Yet, once it’s installed, all you see is real, natural hardwood patterns. That’s the joy and peace of mind of a floor with natural beauty and engineered toughness. Designed by Nature, Perfected by COREtec.”

At this point, the job ($4/sf for a BIG job with LOTS of things to do = awesome price) is finished. The cure is going to be worse than the disease. I'm a big fan of "Wait until you have a problem before throwing money/time at it." It is the cheapest solution I know of (I'm a pragmatist...who is both cheap AND lazy ;-P). My advice is this: leave it alone. Keep 10% 'extra' of the flooring product (roughly 75sf or to the nearest box). This will offer you the peace of mind and the material security you will need to feel secure. You will keep it in the back of your mind. You will know that IF something goes wrong you have ALL THE PRODUCT needed to repair/replace the damaged planks. With a laminate floor I wouldn't worry to much about a bit of bounce. People have 'put up with' bouncing laminate floors for 20 years (the SAME laminate they installed 20 years prior). That tells me the click system is fine. Your floor is a rigid vinyl (8mm thick = nice product). The rigidity of the core will help keep everything stable. The only weak point (as in everything in life) is the link (click edge) between one plank and another. This is the one and only place things *might go wrong. Now to be blunt, a rigid vinyl floor like yours can be taken apart and, "in theory", be clicked back together - BUT I don't like that idea. I really don't. We know the click-edge is delicate. We know that. We've seen them brake by grazing the ground before being installed. A vinyl floor that has been disassembled has a STRONG likelihood of DAMAGED edges. If the edge is damaged then there is almost no way you will get them back together. That means you will have to assume 25% damage should you choose to 'unzip' this floor to the point where it bounces. That leaves you with 75% intact flooring with 25% garbage planks (which must be replaced). As soon as you try to fix the subfloor underneath (by removing the flooring) you will have lost the 'intact' floor. You are guaranteed to spend MORE time, MORE money and MORE materials to deal with this. Compare that to 'leave it alone'. Right now you have 100% intact flooring. Every day you wake up to 100% intact floor is another day with a perfectly functional floor. Every day you have 100% intact floor is another day you have SAVED time, money and materials. Simply leave this floor alone until something MAKES you repair it. Keep your 5%-10% extra on hand for future repairs (and there will be future repairs). Use them if and when you need them.

I preface this reply by saying that it may step on some toes and is not for the easily offended... Think of your floor cleaning like your teeth cleaning: you can brush, floss, and gargle on your own to your heart's delight. But at the end of the day, it can't replicate the cleaning performed by a hygienist in the dentist office. In other words, you need to have a professional cleaning company periodically clean your vinyl floors. I know, most of you DYIers had it installed to get away from carpet, tile, and other flooring that has traditionally required professionals to maintain. Truth is, you DO NOT own the equipment needed to get these floors, particularly the ones with a textured profile, completely clean like they were prior to install. And while the flooring companies didn't outright lie to you (calling it low maintenance rather than no maintenance), they certainly led you astray by letting you to believe that a little hot water or their overpriced, product-specific cleaner was all you needed. So, find a reputable local cleaner to professionally clean your LVP floors. Got kids and dogs? Do you go barefoot or wear outdoor shoes in the house? Get your floors professionally cleaned every single year. The rest of you? Every 2-3 years. In the meantime, stop using steam. Stop using acidic (vinegar) and high ph (ammonia) products. Dump the bleach, Murphy's Oil Soap, Rejuvenate, Bona, Mop n Glow, Orange Glo, and all types of polishes. Only use a neutral cleaner in between professional cleanings. Oh, and those area rugs you put down to cover up the unsightliness of your floors? They're likely voiding your flooring warranty (probably not a big deal because many have already done so with their unapproved cleaning methods and lifestyle).