OP I saw your initial post. Are you sure the phrase uses the BIP39 standard?

Can you also give us an update of the words you know (or perhaps the one you have found during these 2 years) ?

Let me guide your answer a little bit:

word 1 - known
word 2 - known
words 3, 4, 5, 6 - you only know one word for positions 3 - 6 but don't know it's position, so you basically have 3 missing words in these positions?

words 7, 8 - you know the words but don't know the positions, so you don't have any missing words, but only ther order missing?
words 9, 10 - you know the words but don't know the positions, so you don't have any missing words, but only ther order missing?
word 11 - known
word 12 - known