if not what other tools you'd suggest for trustless bitcoin multisig remote signing?
It can be used offline, so if it's just signing that you need, you can be assured that it'll be safe if you use the tool on an Air-Gap machine.
And also, it's open-source, you may personally or ask an associate to audit the code and use it instead of the website so you can be sure that you're using the code that you've reviewed.
Don't just trust the poll's result, verify. (
"don't trust, verify")
The links to its GitHub repository and offline files are in the website's footer.