which gel should I choose ?
There are gel polishs that don’t require an LED or UV light to cure/dry. Generally, any polish that cures under a light has to undergo a damaging process of removing it. As the gel polish that drys like normal polish won’t require the steps for removal of a cured gel polish.
In my opinion, no. The thing is, if you’re only getting gel polish and constantly taking it off/changing color then yeah it can be damaging because the nail tech is probably scraping it off or constantly filing the surface of your nails which can thin them out over time. If you just had a gel manicure they should only be filing where there is growth, not the whole surface again.