You want me to have email and teams/slack on my phone? Sorry, I won't install the spyware. Want to pay for me to have a second phone with it? Okay. No? Well then, I just won't have email on my phone.
It needs to be made illegal imo. The company should provide you a device if you need one for the job.
Scenario: Your account gets compromised somehow. It's signed in to your personal phone. Company data gets leaked or ransomed.
Your phone and its contents are now evidence.