I didn't know any of the tools sorry for my ignorance! I am looking at it rn:

nsecbunker looks pretty neat, it's on desktop though. I think I am going to give it a try, I need some people in my team to be able to do posts on our label page and that seems to help for the case!

bitwarden seems to be a password manager on mobile and desktop, with syncing capabilities. It has a public API but it doesn't seem to focus on message signing. To enable a single application to sign messages on other application, the two softwares needs to communicate. Application on phones are isolated for security reason.

the difference between the two is that one (nsecbunker) is only desktop? and that one has syncing capabilities (bitwarden) but in my opinion this makes it less secure. And also all those logos on bitwarden site are making me suspicious about it hihihi

I'd go for nsecbunker

that's my best guess! as far as i can see from a superficial study of the cases ^^ =)