Agreed; you’re not alone.
It seems to me that when one opens a new tab, the focus should shift to that tab. You mention that’s the way Firefox works. Brave (Muon) also offered this as an option. (Choices are great!)
This is a furrow that’s been previously plowed:
Repeating my request: offer this as an option. Choices are great! There’s no one-size-fits-all.
Unfortunately, Brave doesn’t appear to be responsive to this request.