You have a preferred theory already, and you're trying to fit the facts to it.
Unwise.
Unwise.
In human language there are often similarities between unrelated languages and these have myriad possible origins. As such, within the realm of linguistics one needs substantial proof to successfully claim a relationship exists between two otherwise unrelated languages.
It was only a little time ago that many historians insisted bronze-age tin could not possibly have come from England. ("There's no solid evidence for it!") Then isotope analysis showed that it definitely did. The only correct statement at the time would be that we didn't know whether the tin was coming from England. Accepting the isotopic evidence does not absolve anybody from insisting they knew what they were fully aware they did not know.