When sealing paint on glass?

https://www.ehow.com/how_4815659_seal-acrylic-paint-glass.html

You make what they call a "Slurry". You water down a small amount of cement and use your hand and smooth into the holes. You may have to do this 2 or 3 times. When doing your cement and un-molding, best to check for holes at that time and wet your fingers and gently smooth over the holes and they will disappear.

I would apply very light applications of spray clear coat, and get a spray with a fine mister tip.

I painted a mason jar and then proceeded to coat it with a clear sealer. It pulled the paint, which made me very upset. I'm wondering if spraying the sealer on would be a better option.

Here's a tutorial that might help - https://chascrazycreations.com/painting-glass-diy-guide-and-tips/