They do a similar job, they’re different products. Straight acetone is a solvent that strips everything off the nail (oils and moisture) and it’s pretty aggressive. A nail dehydrator is usually a blend of isopropyl alcohol and ethyl acetate, made to flash off surface oils and moisture fast without soaking into the nail plate the way acetone does.
The bigger issue for your nails sounds like the repeated soak-offs. I went through the same “it’s not perfect, rip it all off” phase and paid for it for months.
My wear time got noticeably better once I switched from the acetone-then-alcohol routine to a proper dehydrator. How Do You Dehydrate Nails?
Keep the dehydrator on the nail plate and off the skin, and use a base coat made for peely nails. Cuticle oil helps a lot too, not right before you paint.
The dehydrating step itself is fine unless you’re doing it five times a day. It took a couple months for my thin spots to grow out.