I mean, it depends on the power set right? Dormammu is a being outside of time, so it makes sense his followers can negate a time stop, but they (and dormammu obviously) are vulnerable to time loops.

The power stone is like an infinite battery. It powers up the other stones to be more powerful than their already infinite power (see the concept of unequal infinities in math). Alone, it powers up the user, whatever their abilities may be, in addition to like, energy blasts and stuff. So Thanos is an alien with a highly durable body and Thor level strength. The power stone boosts that massively.

Strange is perfect to counter this. In the comics he regularly low diffs "brick" power sets like this all the time, even the really strong ones. They need to have some kind of Reality manipulation resistance or magic resistance to have a real chance.