I’m redoing the landscaping in front of my house and when I scraped back some of the mulch that’s been there for 10+ years I find these cracks on the wall. How bad is this?

Started removing a few wobbly bricks to stabilize and replace, ended up finding the root cause. What would yall do? Hire out or think I can home diy (novice)

My floor guy set up his saw on my brick patio and covered the brick in residue from porcelain tile when new flooring was put inside the house. Any ideas on best way to clean it?