Child Car seats in CX-9 Captain's Chairs?

Hi, new owner of a 2021 CX9 GT with captain's chairs. I need to move my daughter's car seat/high back booster from the old car to the new captain’s chairs. I'm wondering if anyone has used something underneath the child's car seat to protect the seats? I used something in my 2010 CX9 with cream interior and it left black dot marks all over it.
 
Thanks. That sounds interesting. Where do you find that? Is it just in a white color? Do you put it up the seat back too?
 
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Mazda CX-9 Signature
I basically cut out slightly bigger than the base of the car seat to help distribute the pressure points. I'm happy with it helping preserve my sig Napa leather.
 
My mrs got these from ali. Took a while to arrive, but cheaper and better than we could find from the local stores. Quite thick with padding inside to protect leather from base of the baby seats. Also has the slot cut out for isofix
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