How is this person forcing you? Are you an adult? So they provide the material benefits for your life, like good and shelter?
If "yes" to being an adult, and then "no" to being a dependent or an employee, then this requires a lot more conversation.
If you have an android phone, you can make use of FDroid and Islands/'Insular' (without root access) to have a separately secure side of your phone for apps and system settings.
For example, I loaded all of my work apps in there and then set a VPN so that ALL OFF THEM were unable to connect to the Internet when the VPN was offline, so that the ip-location and the DNS didn't tattle on my travels. My regular phone use was secured away to the point I couldn't accidentally send photos from my regular photos app through my work email app, only the second copy that lived within that 'secure folder' style partition.
Obviously your situation is harsher but at least you can mitigate a bit by being able to offline the app for considerable intervals, this way.
Good luck. I hope that you share more of this story.
Edit: I see you are stuck on iOS. I have zero suggestions for your specific situation besides "work on the relationship, and your always have the right to walk away from the business or the adult relationship if it's untenable."
Hey, thanks!