Same for merge conflicts. I’m not sure you can even resolve them on the CLI
How are they solved when using a GUI? When using cli, it simply tells auto-merging failed and you can open the conflicting files in a text editor and solve the conflicts, then add them and continue the merge.
Managing branches: perhaps I’m a little too ott but I keep a lot of branches preserved locally, a GUI provides a decent tree structure for them whereas I assume on the command line I’d just get a long list.
git log --graph --all --oneline

There's also --pretty, but it uses a lot of screen space.
Managing stashes: unless you just want to apply latest stash (which admittedly is almost always the case) then I’d much rather check what I’m applying through a GUI first.
You can attach a message when stashing with -m.

And you can check them out by doing git checkout stash@{1} or similar.