The problem
Shopping and PMax do not give you keyword control, so brand searches land in the same campaigns as everything else and inflate them.
What you can do
- Run a dedicated brand Search campaign so brand demand has a cheaper home.
- Use campaign priority and negatives to steer brand queries away from catalogue campaigns where the account allows.
- Exclude brand from PMax where possible.
- At minimum, measure it: compare branded query volume against campaign performance over time.
Related: why the split matters.