This is a killer app. There have been times when I asked someone "why can't you just send me a screenshot on signal" or "Oh, can't you copy the URL to your desktop?"... only to realize that the poor fellow didn't have KDE connect (yet).
It's not perfect, but it does things I haven't found anywhere else, makes your phone and laptop and pc.
It might help that I'm actually running KDE everywhere, of course.
I've always run GNOME and KDE Connect port called gsconnect [1] works very well. I run it on several Ubuntus and on Debian 11. I run the KDE Connect app on my Android devices. That plus syncthing are exceptionally good tools to link all my devices together.
It is less about messengers per se, itnis about interacting between devices.
I can share clipboard contentents, can send files, send web page urls from phone to desktop to open a browser there, can control media playback between devices (switch to next track/pause desktop from phone and vice versa) etc also I get phone notifications on desktop
Silly use case but I watch TV on my laptop in bed and the cat likes to watch with me. I use some ancient X11 app to freeze the keyboard and mouse and then control vlc, etc. from KDE-connect. That way when my cat attacks Jedis he doesn't reboot my laptop.
I can share links to myself with a messenger but it's much faster to share them to a given device and see its browser open a tab to that link. It works inside apps too: I can share a video from phone to tablet (NewPipe, probably YouTube too, it's the Android builtin sharing system.)
I can also stop, resume, control volume of media playing on another device.
I can share the clipboard, send files, use a remote keyboard (I think I disabled it) and ping a device.
It can do a lot more but I'm not using much else, I think.
It's not perfect, but it does things I haven't found anywhere else, makes your phone and laptop and pc.
It might help that I'm actually running KDE everywhere, of course.