Cannot configure external diff tool Mac. Help please.

[Steven Hennessy]

Mac: 11.2.2 (20D80)

Sourcetree: 4.1.2 (237)

I have tried a bunch of different solutions on this forum but still cannot get this to work properly. Can someone help me get it configured? Crazy this is such a painful task in setting up an external diff tool

I have tried FileMerge, BeyondCompare, etc. but no luck