First, I am assuming you’re using a. Babylon format. Not sure if your producer does this, but I found after the first frame, that bones can be excluded, if the value is the same as the previous one.
Next, 4 digits of precision are enough. Plus a dot, a zero, and a comma gives 7. Zip then makes even slightly better than binary like gltf. To add, I also do not do trailing zeroes. This is useful, as certain elements of a bone matrix don’t even have decimals. Scrap the dot in those cases too.
I am not sure Draco compression would help much with animation. Could be wrong, but thought they get much of their gain due to vertex indexing. Babylon format does that. Also don’t know if bone elimination trick works with that path / gltf.
Also, you have too many bones. Sorry, but just because you can render that many, does not mean that there will not be issues. Animation size being the prime one.