You happen to have it wrong especially on Miriam and Moses’ wife. Miriam did have the wrong attitude but not for the reason you think you know. There were important reasons for Jesus to have been born through a pure line of Israelites...and your deduction on Ruth blows that aspect apart.
Might be important, but it didn't happen. Let's leave aside all the unknown foreign wives that were never recorded.
The minimal record we have, mostly of the women in the royal line of his ancestry, indicates numerous Ammonite, Egyptian, Tyrian and other foreign mothers of the kings.
Christ's human ancestry, like that of every other person on the planet, was not "pure," it was thoroughly mixed.
The Israelites themselves were never a "pure" race, in fact their Law contained specific provisions for marrying foreign women captured in battle. As one example, Joseph married an Egyptian women. Therefore, his two eponymous sons, Ephraim and Manasseh, were half-Egyptian.