something I’m bad at is like, expressing broad disagreement with people?

I can express disagreement on specific points, when I’m prepared to back up and defend it. like “I think your study protocol has X problem” or “I think your claim is undermined by Y data” or something

but a lot of the time my disagreements aren’t that, it’s like “I have a generally negative impression of the quality of your work” or “you’re making a lot of claims I can’t personally evaluate but don’t trust your judgment on” or “I think our goals just aren’t very aligned” or

so I think I just smile and nod in these situations and people end up with a mistaken impression I agree with them more than I do

but like, idk what the best alternative is? because a lot of the time it might make sense to work with them anyway and like. do you go around being like “I think you’re probably full of shit but yeah I’ll give you some resources on the off chance you’re not”?