Over what time span?

If what you say is true we should have seen trust in the media go up and down a lot over time. In fact it's really only gone down, with one exception - in the USA after Trump got elected trust in the media went up amongst Democrats only. Presumably because they realised the media was completely partisan and in their "tribe". Trust amongst Republicans, which like Democrats had been falling for a long time, completely collapsed at that point.

In most parts of the world it's just been one downward slide.

In these events I don't think the media deserve the blame though. They're not helping but they're not pushing a pre-determined agenda, I think. The evidence that we're in the grip of mass hysteria and not a deadly pandemic is growing enormously every day, and much of that evidence actually is being surfaced in newspaper reports. It's just not affecting the overall narrative yet.

But again, you must see the problem here. To consider the media's credibility a resource at all is a post-truth concept. It presumes that the media is targeted towards a bunch of rubes, who've gotta be manipulated towards the goals you and I know are best. The natural result is exactly the trend we're seeing; almost everyone who pays attention says "well, I'm not a rube, so I guess I'd better get my real information elsewhere".