How to find files in the Finder
~/.m2/ has a dot as the first character of the directory name. This is a hidden folder, so isn't indexed by Spotlight. Finder won't find this because it's not in Spotlight's index. Rename the folder without the dot for the folder to be indexed.

Searching with Finder uses Spotlight so should be near-instantaneous. You can show the status bar with View → Show Status Bar (⌘/) and a pinwheel will appear at the right of the bar when Finder is still searching, disappearing after the search is complete.