Can we move to m365 instead of an on-site server?

[NoobTech]

We have an SBS 2011 Standard server in-house with 15 users.  A few years ago, we moved email off the server to m365.

So the in-house server is only a file server and domain controller.

With it on its last legs, can we get rid of an in-house server and use m365 for file sharing (and domain controller tasks?).

I'm not looking to 'spin up' a server on azure.  I'm looking to have Microsoft take care of the 'server'.  Like I don't have an exchange server anymore - not in the office, not in the cloud (that I have to take care of).  

Sharepoint would be the replacement for the file server.

Do I need a domain controller?  There's different tiers of azure active directory.  Can that satisfy the domain controller role? Which would I need?

Is there any step by step migration docs out there?  I know I did a swing migration from SBS 2003 to SBS 2011 years ago.  A step by step process.

Looking for something like that to follow if m365 would eliminate the need for a server.

THANKS!

[#2]

Hello @NoobTech 

You can use the SharePoint Migration Tool tu Upload your local files to SharePoint.

https://docs.microsoft.com/en-us/sharepointmigration/introducing-the-sharepoint-migration-tool 

Instead of a local Domain Controller you could join the PC to your Azure Active Directory.
https://docs.microsoft.com/en-us/azure/active-directory/devices/azuread-joined-devices-frx 

If you need a Domain Controller you also can use a Service in Azure called "Azure Active Directory Domain Services". https://azure.microsoft.com/de-de/services/active-directory-ds/