well if you're looking for people to test the filament - I'm up for that :-)

I use quite a lot of flexible filaments. Currently tedn to use flexismart for anything needing rubber like properties.
e-sun flexible (just) pla for projects that need to be both stiff and have some flex.
And polyflex for the vast majority of flexible projects. Including the world's only 3d printed sling pouches :-)

I don't think any of them are what you'd call biodegradeable.
So would be interesting to compare yours with all the other ones I've used.
Plus have two different extruder setups, so that would be interesting as well.