I used Bitlbee until not that many earth rotations ago - it's an IRC daemon that provides bridging of various other chat protocols. It worked way better than you would expect, especially back in the day when you could use XMPP to connect to the various proprietary chat services.

I didn't stop using it until I stopped caring about those chat services.

These days I run a Matrix home server with bridges to Slack and WhatsApp so I can use fewer chat clients.

I do wish the Matrix client situation was less messy.