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.
Bitcoin is whatever node runners choose to run in open-source software, whether that’s Core, Knots, or another client. Any incompatible hardfork just creates another altcoin, no impact to Bitcoin.
There's been so much misinformation and noise about this topic, it's been disappointing to see.