The issue I had with your post was this...
"please don't recommend anything else"
You asked the question before and were told to be safe, use only silicone because that IS what is used professionally. You asked for advice (that's good!) but didn't like the answer?
Hot glue COULD be perfectly safe for amphibians, but I don't know this for sure. All I know is that silicone is used professionally, and there HAS to be a reason for that. Deviating from a widely accepted norm (using silicone) is a risk (in my opinion), and thus an unnecessary risk when there are other suitable materials available.
I personally have experience using inorganic materials that were actually marketed for herp use. It directly resulted in the death of 8 red spotted newts before I caught on to what could be causing it. When it comes amphibians, I don’t trust materials that are marginal in compatibility. I prefer no risks. THUS the recommendation of silicone over hot glue.
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...the oldest task in human history: to live on a piece of land without spoiling it."
Aldo Leopold (1938)
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)