I definitely don't think that's correct, or at least, certain demons are exceptional just as certain humans are exceptional. The hero party we saw was only one of them and it was lauded for its successes precisely because the threat was very real. Qual remember was so dangerous that they couldn't actually defeat him at all but merely managed to seal him. 80 years was enough of a freeze and human development fast enough that new generations could counter him, but even so he managed to almost instantly analyze the multi-year-development extremely complex defense magic created to counter Soul Track. He was definitely not a being to allow to get away, Frieren correctly finished him right off but if he escaped and had a few years to do his own R&D there is no telling whether he might have developed a counter-counter himself.But against wizards or warriors prepared for their Modus operandi they're probably not that dangerous.
...however much less happy to see that slavery/rape isekai so high up on the list as well.