You don't always need the hash id. @ is equivalent to HEAD, there's also @- for HEAD~, @-- for HEAD~2, etc. with jj log the revset can also be a complex expression https://jj-vcs.github.io/jj/latest/revsets/. You can also create a bookmark to track a remote git branch that's also updated when you fetch. But you have to move the bookmark when you make changes locally.

I can see that - but that's a "less frequent" task than me switching between branches.

My observation is that one happens to edit the commit graph much more often because it is so effortless.

And the analogous thing to switching a branch is:

jj

to get the log. And then, with say "qx" being the abbreviated commit id I want to append the next change to:

jj new qx

and now I am already working at the right series of changes.

Because I like a lot to focus on one single thing, the next thing I do is often

 jj desc

which opens $EDITOR with the commit description and lets me write down what I am going to add or change.

That commit description also shows up in the log command, so I know always what the change is about.