California: Recruited with written promises, both changed after I joined

Location: California
I was at a company I really liked. Strong bonuses, I worked from home, and I traveled internationally on a regular basis (which I didn’t like).

An executive I knew reached out about a role at another company. I liked their products and already had friends working there, so I was open to it.

Two things convinced me to make the move:

I would work primarily from home and come into the office only for important meetings.

I would receive a bonus of 30% of my salary.

These terms were negotiated over an email thread before I accepted. The executive who recruited me went to the CEO and got confirmation on both, and that confirmation is in the email chain to HR.

I accepted the offer based on that.

The offer letter says: “minimal travel, work primarily from home, and 30% of salary bonus.”

Since I joined, both now have recently changed. A new company policy now requires me in the office 3 days a week (at least an hour each way), and my bonus is now being set as 20% of my salary (stating “all the VPs are getting 20%”)

I'm deciding whether to stay or go back to my previous employer, and I'd like to understand my options first.

Questions:
Could this support a fraudulent inducement or promissory fraud claim in California?

Does it matter that the office requirement came from a company wide policy rather than a decision about me specifically?

Does the CEO's email confirmation carry more weight than the offer letter if the two don't match?

Is there anything I should do or avoid doing now to protect myself?

Author: Hot-Difference7736