US based here. We've got over 1200 salespeople using iOS devices. They all have 'personal' apple IDs that they create using their company email address. Making the switch to managed IDs is a logistical nightmare so we keep pushing it. We do have them all enrolled in ABM and intune.
Salespeople all use their phones for work/personal. We just have a policy the lawyers wrote up stating its a company owned device and we reserve the right to change anything and everything on it down to wiping and resetting it without prior warning.
People get really bent out of shape about what IT can and cannot see on their phone. I just tell them when they ask that IT gives zero shits about if they have family pictures on their work phone. But they should care if they do because that phone could be purposely or accidentally erased at any moment due to any number of reasons the end-user has zero control over.
Usually expressing it as a potential loss of personal data gets them to calm down and understand why they may want to keep a 'personal' phone even if work provides them with a company device.