I went through ssh in .config and backed up and deleted /okboard and edited /maliit/server.conf which was refering to ok board. I left that file & folder, but deleted its content.
Keyboard is back - problem solved. I can use my phone again!
So there were no other keyboards activated under Keyboards?
Normally this should be possible without a keyboard by selecting/enabling another keyboard layout there.
For anyone else getting caught out by this, you could also edit the mailit/server.conf file in the Terminal app as it has its own keyboard that remains unaffected by this