"Some of the propaganda contains truth" is a weird ass sentence that cannot really be framed in any other way than someone supporting said propaganda.

It's like saying "some of the conspiracy theories contain truths", it only works if you believe in them.

Information used to manipulate is useless, trying to cherry pick what is "true" is absurd. It's like seeking a mouldy bread just to try to pick the edible parts, instead of trying to get a proper loaf of bread.

Hmmh. It's likely a "the only winning move is not to play their game" situation. Upside of institutions like the BBC is: in theory they should be doing fact checking, pay experts to look at it and see if it's plausible, try to find the sources... Try to show both sides of a coin. Doesn't always happen in practice... But if your alternative is to re-post stuff from social media or random internet sites... Well... you're exactly in propaganda territory. That's unfiltered where all the evil people post their fakes. Have bot armies to push narratives. Make it seem like roles are reversed.... And you're bound to lose. It's a proper paid full time job to push propaganda online (and offline). And those people are experts and they're resourceful (and have resources, i.e. money and access to stuff). They'll likely outsmart you, beat you with all the manpower they have at hand, and you're just a pawn.

And to not only write negative stuff: I somewhat trust the OSINT guys. Dunno if that's what you're looking for. They do a lot of quantifying stuff. And some more. Less so opinion pieces or news articles.