I am putting new laminate flooring down and they had stick and go tiles down
I don’t know if there are more ways to do it, but I used an inexpensive heat gun and scrapers (various size putty knives)
It was still sticky, but smooth. I was also using rolls of underlayment, so the residue wasn’t an issue.
Here are some instructions... unfortunately, sounds like you'll need to warm each one with a hair dryer: https://homeguides.sfgate.com/remove-self-stick-tiles-49728.html
Maybe something like Krud Kutter, an adhesive solution/remove would get the remaining glue off?