Cloudflare and NextDNS absolutely counts as "some random company" in this context. I have no reason to trust random American companies more than my local ISP. I don't trust the USA more than I trust my own country.
You know you are quite fortunate to be able to say so.
Firefox is a project with global impact. A lot of people around the world can benefit from DoH.
The German Grundgesetz (constitution) says "eine Zensur findet nicht statt" (censorship does not occur/there will be no censorship) yet, there is censorship.
I was sceptical about DOH in general (why do we need this?) but now I see why this can be a good thing and great as well that Firefox supports it so easily.
I'm not going to search for every single article. Or are you seriously suggesting that Reuters is 100% free of propaganda, especially in war times?
The answer your question: "common sense".
I don't care about either side of this argument, but you can't logically turn the question around. The burden of proof is on you, who made the claim.
Like "don't get caught by your own gov accessing restricted material get caught by USA gov-related organisations so they can sell you out to your own gov & benefit USA".
If you're bothered about who's watching your web traffic then it seems highly unlikely you want to add USA to the list of who is watching you??
And the States are watching you anyway: most of the Internet resides there. Even the websites that don't are likely using Cloudflare or etc to save on traffic.
I'm in Canada and the default provider is CIRA. I can also choose to switch to Cloudflare, NextDNS, or add my own.
You can check out the Network Settings at the bottom of the General tab to see what your default is.