Should I drop dbo from the database role db_owner? I did a Vulnerability Assessment for my database today. I found VA2108 and it suggests me to
ALTER ROLE [db_owner] DROP MEMBER [dbo]

But it's the default setting of any SQL instance.
Should I go for it? And is there any risk?

Thanks
Don't worry about it, as J.D. says.
In fact, you cannot drop dbo from db_owner. There's a hard-wired blocker in the engine prohibiting you to do so. Try and you get the error:
Msg 15405, Level 16, State 1, Line 1
Cannot use the special principal 'dbo'.