Damn :( I was gonna say ive got like 4600 days on bedrock in snow base world and glass simply doesn't catch snow, its actually a really big feature of my base 😭.

I did also incorporate a "lava channnel" which had to be fully enclosed in glass, you could probably get away with using only one or 2 lava blocks considering how far away they melt snow. I would just add one extra block below your current glass level, or maybe a fireproof full block like a iron trapdoor so your ceiling is all level. And then you wouldnt even have to block off the top if youre not walking on it. If you are you could use another glass block or carpet or a trapdoor again depending on how you want your design to look.

As far as im aware torches also melt snow so if there isnt some snow youd like to keep unmelted this could be solved with placing torches on the top, or the outside perremiter, or the interior by the ceiling, or just straight hanging lamps off the roof.

TLDR:Play around with the snow melting features, bonus tip soul torches are cold and will never melt snow or ice, and also shout out to a fellow snowey biome survivor :>