Employer Work Phone and Dual-Sim

Hi Community! First post here.

I'm using an employer-provided iPhone and I'm not sure who to ask. Feel free to let me know if this isn't an Apple question.

I recently converted my personal physical sim card into an eSim so I could use it jointly with my business sim in the iPhone they've provided to me. I just didn't want to account for two phones. That being said, I know there are certain contracts that Apple provides and I just want to know if there's any information disclosing how much boundary the employer has when it comes to my own personal privacy through my personal sim. Would my employer have access to my personal phone calls or texts?

Any and all advice would be appreciated.