I've done the same with https://github.com/42wim/ssh-agentx/
Originally used to sign git commits with pgp in the sshagent, before ssh git commit signing was a thing.
Also works with windows as it uses https://github.com/buptczq/WinCryptSSHAgent that did the hard work to get it to talk with almost everything that exists in windows/wsl/putty etc.
https://github.com/42wim/matterircd for example
You can use your favorite irc client to connect with the ircd to talk to slack (of course it has almost the same limited irc issues)
Tested on almalinux8/9
https://gist.github.com/42wim/2e3cc3c92333e4c2730541e6f0e038...
YMMV