I would like to be able to assign a default dashboard to a new user.
I think it exists but with a bit of gymnastics.
When you edit a dashboard, you can change its name and make it either available to everyone (public) or just for your user (private).

From there, go to your user’s profile, create a dashboard (private or public) and place it at the top of the list.
That way, when the user logs in, by default they’ll have the first dashboard, which will be exclusively theirs.
Another, simpler option: if you already have a public dashboard for that user, you just need to log in as the user, edit the dashboards and move the dedicated one to the top.
In my example, if I put Weather first for that user, that’s the one that will be displayed when you click on Home.
PS: I’m taking the liberty of changing your category from feature request to configuration if that’s OK with you.
Thank you for the explanation.
It’s fine, but it’s a bit far-fetched. It’s not a priority, but I think being able to assign the dashboard directly to a user would clarify everything.