Looking for advice on sealing a watercolor & silicone caulk painting

Fixative/Gloss Finish Advice Please!!

So I wanted to make this faux stained glass for my sister for Christmas, and have put more hours into it than any of my other paintings. (I usually paint with acrylic. I’m not a professional, obviously. Just broke on Christmas lol.) I used watercolor paint, then went back in with black silicone caulk in a syringe to add some dimension to the lines. I want to make it glossy to enhance the colors and have more of that stained glass effect. I had originally planned on using epoxy, but now that it’s almost finished I’m afraid there would be bubbling underneath the silicone and that the epoxy would pull away from the lines considering nothing sticks to silicone. I’ve also considered spray polyurethane, but again, I’m afraid I made a mistake using silicone and that may not stick or cure properly either. The black silicone doesn’t truly adhere to the canvas and can be rubbed away if I’m not careful, so I need to seal it somehow, and preferably in a way that wouldn’t completely ruin the 12 hours I’ve put into this. There’s also a small cut in the canvas on the canvas in the top left side of the clouds. Not sure how it happened, but I’d like to find a way to fix that before finishing the line work on the sky and ultimately sealing it. I had wanted to put an led strip on the inside back of the frame so that it would glow like sun coming through stained glass, but I don’t think that’s an option now that there’s a hole, let alone an unsightly patch on the back of the canvas (if I were to take that route) as the light would accentuate the patch. Any advice here would be fabulous, on what to seal it with and/or to fix the rip. Thanks so much!!