I was reading about kitty-scrollback-nvim and one of the comments mentioned that they didn’t see the point because modern shells had a way to edit the current line in an editor. I had seen this in bash before, but had forgotten about it.
I “searched it up” for Fish and found out that, yes, Fish supports this, too, but with ALT-e as the shortcut. It works great! It opens a tmp file with the current line in it and then you just save and quit to go back.
See the Fish docs on the command line editor for details.