If you are able to connect via USB it's very unlikely that it's the fault of your config files. But to be honest, if you are really in the same network and use the correct ip, I have not really a clue what can be wrong.

Are you sure it's the fault of your Jolla? Have you already tried to reset the authentication keys?

I assume you can at least ping the Jolla and get a response.

How to reset authentication keys? I deleted whole ssh folder, and have not set a password for ssh, if this is what you mean.

In meantime, i ran again pkcon remove and then install for the openssh-server, the etc/ssh folder has been recreated, but still not possible to connect.

So i just restarted my router... guess what.. it works!

Thank you all for your support and efforts! Solution was literally under our nose

I got that. But maybe it's not just the fault of your jolla, but there is a problem that something in your network or your Jolla has has changed, and for that reason there was created a new key.

In that case you have to delete the key on your PC, because there is already stored a key for your Jolla and if that for some reason doesn't fit anymore, there is no connection possible.

If you delete this key on your PC, it should ask you on the next connection if you trust that key and if it should be stored. If I got it right, you are on Windows and use Winscp. As far as I know there is somewhere an option for deleting the keys - don't know that for sure, I'm on Linux.

The best way to exclude a key problem is to use another computer, which wasn't connected to your Jolla yet.