Different implementations are non-partisan and perfectly fine as long as consensus rules match. Like you said, Knots is basically Core with extra relay options, and for Core/Knots team to deviate into hard-fork territory would be an insane move, and bad for Lightning.

The good thing about Bitcoin is we don’t have to speculate on compromised teams or people; the code speaks for itself, and everyone is free to choose which open-source software to run.