Unsure about Apple Business Manager on personal devices

Hi everyone!

In the company where I work we need to plan the deployment of Apple Business Manager since all employees have company-owned iphone and ipads. Unfortunately there are a few employees who still need to have their work mailbox configured on their personal iphone as well as a couple of them actually not holding a work phone as they chose to use their personal for work as well.

What I'm trying to find out is: how will Apple Business Manager affect their personal devices once it gets deployed? Will they lose any functionality on their personal iphone? Is there any cons or anything I need to make them aware of before deploying it? I tried searching on the web but couldn't find any concrete answer so thanks in advance to anybody who can shed some light on this! :)