Managing Macs with personal Apple IDs

Hi all,

I have a client that is 95% mac, 100% remote and using Google Workspace for email, file storage, etc. The macs are company owned, but everyone's iphone is personal. This is 50 users and growing. Everyone expects to use their Apple ID on both machines so that all the goodies like messaging, file transfers etc work for them. So we can't really take advantage of any MDM for the Macs that requires us controlling the Apple ID. How would you best manage this scenario with what you can control?