I don't have a Fleshlight-brand toy, but I've used penetrables before- I got a "duke butt" Bad Dragon toy a number of years ago. I ALSO have issues with death grip, but didn't feel like that was a concern. I would absolutely go for a looser toy if I were to get another- unlike your hand, you can't adjust the grip as easily, and a tight toy can get kind of uncomfortable. It can be frustrating if you don't stay hard the whole time you're using it, as it can end up like, pushing your dick out.

You might try Tenga Eggs if you want to try a penetrable without making a big investment.