This article is just sensationalism that wants to attribute any excess deaths throughout this year not officially recorded as covid19 deaths as possible covid deaths. This kind of nonsense is not helpful. The article itself admits there's plenty of other reasons that could be attributed but that it should still be considered. Padding numbers with speculation does not help form good decisions.
The graphs for Austria and Portugal are interesting. They show historical peaks earlier in the year, probably caused by the flu, that are higher than the current spike caused by the coronavirus. Especially for Portugal, the past peaks are way higher. That would seem to suggest the current numbers, while high for the time of year, are not completely unheard of.
Title should be "Global coronavirus death toll could be 60% higher than reported"