Can I force my emails into the Primary tab?

No, you cannot force Primary tab placement:

Gmail classification uses machine learning that considers content, sender history, and user preferences. There is no switch to flip.

Attempts to game the system often backfire. Stripping HTML to look "personal" when sending bulk commercial mail creates mismatch signals that can trigger suspicion.

Users can manually move your messages to Primary, which trains Gmail on their preferences. But this is user-controlled.

Focus on delivering valuable content that users engage with rather than trying to manipulate classification.

You cannot bribe the dock master. Deliver good cargo consistently and trust the process.