To my understanding, in a normal non-conditional clause “どうせ” has a function of saying that something makes the surrounding context irrelevant, similar to “anyway” in English. As in for instance “あのパーティーにいるかどうかはどうでもいい、どうせ行かないから。” for something like “I don't care whether he'll be at that party or not, as I won't be going anyway.”
But I'm often encountering “どうせ” in contexts with a form of “〜だろう” attached where it seems to have a very different meaning that I can't find anything about in any particular resource, rather seemingly emphasizing the speakers expects something to be the case in a dismissive way. For instance something like “お前たちはどうせなにか企んでるだろう。” for what seems to mean something like “I bet you guys are planning something.”, seemingly losing all of the normal connotation of “どうせ” that it makes the surrounding context irrelevant as I often encounter it contexts where no such implication seems to make sense.
Is my understanding correct that “どうせ” often loses this implication of marking the surrounding context as irrelevant when coupled with “〜だろう”? or is there more to it what I don't understand?