It’s a corporate engagement ring.

Article mentions it amounts to ~5% ownership

No, but it's still a big stake from the largest player in semis. You wouldn't expect a move like that if they didn't see an opportunity there.

Seems like when Microsoft invested in Apple to keep Apple from going out of business and turning Microsoft into a potential Monopoly.

I would assume not given their market cap.

It's written in the article that the $5B represents about 5% of Intel stock outstanding.