Command to search for files with maximum nesting level?

Question

linux

Tell me how to find files on the Linux command line:

1. By content (a specific line).
2. Only with a certain extension.
3. With an indication of the maximum nesting level from the source directory.

Answer 1

find /Path -maxdepth 3 -type f -name \*.txt | xargs grep SearchString

Answer 2

I advise you to use fd