You should not be getting pinch flats that often -- esp. at 100psi. I wonder if you are either installing the tube so that it is getting caught between the tire and rim, or have some other defect or debris on the rim or inside the tire. Carefully check the rim and inside (and outside) of tire with your finger to see if there are any pointy or rough spots. But anyway, if your rims are TL ready, I would consider switching. I've been running tubeless for a few years now and am not going back. If you have enough clearance to go up to 28mm or higher, do it. My bike is older and only allows for 28mm, but it's a big improvement. When I started riding in the 80s, I was rocking 19mm tires at over 140 psi! I can't even imagine what we were all thinking back then.
Edit -- I should add that I ride 44mm semi-slicks and 47mm knobbies on my gravel bike. Wider tires are super plush.