Airside transit is definitely possible, but sources I found suggest that admission into the Netherlands is also possible, if transit is the purpose (note that neither the recommendation, nor Dutch advisory say anything about flying - same rules would apply to ground transit, where there's no "transit area"). The Dutch website also mentions transit into another Schengen state, in which case it's not possible to stay in non-Schengen area anyway. But again, it's necessary to contact authorities to obtain definitive answer. I am optimistic - as far as I know, Netherlands never had their own entry restrictions, they only introduced these to harmonise their policy with the rest of the Union. Therefore I'd expect they are fairly relaxed about it and essentially only implement the bare minimum.