in MN 10 it’s actually a declined form of the word meaning creatures
see meaning 2 at SuttaCentral
satta-creature is declined as sattānaṃ in Gen/Dat case
while
satta-seven - as sattannaṃ
i don’t think the technology is yet advanced enough to automagically parse any lexical unit in order to extract the base word and thus its meaning or derive the meaning on the basis of the unit’s grammatical attributes so there’s no way round doing some chunk of work by hand which in turn requires a degree of knowledge in grammar
Suttacentral’s embedded Pali-English dictionary does is quite successfully but still not in 100%, and the word sattānaṃ falls exactly within those remaining percentages which it cannot parse either
many word forms of the Biblical Hebrew text too are not to be found in the dictionary, because they’re inflected like לְמִינֵהוּ, דְמוּתֵנוּ, זַרְעוֹ
and especially the verbs