How to stop M365 Business Premium from force-deploying Skype for Business?

Hi and thanks for the quick answer.

I'm not trying to block the online service (don't care) - I'm trying to block the client app from installing on user's devices.

After days (!) of research and testing, I think I found the answer.
1. M365 BP doesn't have an easily discoverable way to NOT install SfB. Any manual install initiated by users on office.com will ALWAYS include SfB.

2. When you use Intune to deploy M365 Apps using an M365 App policy (which excludes SfB), it seems to work. At first... But sometime the following day (after about 12 hrs) M365 BP C2R detects M365 Enterprise Apps installed and decides these aren't expected. Seems M365 BP is hard-wired to look for M365 "Business Retail" Apps. So it tries to "update" M365 Enterprise Apps to M365 Business Apps, using Business Premium's standard which always includes SfB. Duh.
The result: Devices now have M365 Enterprise AND M365 Business Apps installed side-by-side (didn't know that was even possible/supported). And since the Business Apps were the last to "update" - they install themselves as the default Office apps all over the place. Including SfB unfortunately...

So what I tried isn't documented in context of M365 BP, but common for E3/E5: I created an Intune M365 deployment policy using a custom .XML config file which specifies:

<Product ID="O365BusinessRetail"> to enforce installation of M365 Business Apps and
<ExcludeApp ID="Lync" /> to block SfB.

>24 hours have passed and it seems to be holding. Got some updates since devices were initially autopiloted and SfB remains off of our devices. 👍

If I don't report back here, this fixed it.

PS. I created the .XML config file here: https://config.office.com/deploymentsettings