New Finder windows are opening in tabs when I want them to open in a new window
To expand on ankii's comment... Have a look at Prefer tabs when opening documents: under System Preferences > General1 where the default setting is In Full Screen Only; however, it can also be set to Always or Manually.
In Finder > Preferences > General when [] Open folders in tabs instead of new windows is unchecked, and Prefer tabs when opening documents: under System Preferences > General1 is set to Always, then Finder will open a new tab instead of a new window.
1macOS Big Sur and later. For macOS Catalina and earlier: System Preferences > Dock