Some Qs on M365 custom themes

Hi All,

I've set up 3 Custom themes on our tenancy (and retained the default unchanged), however the documentation doesn't match what I'm seeing, and was after some clarification.

1) According to this (https://support.microsoft.com/en-us/office/automatically-sending-news-post-digests-with-branding-b930b579-0de5-4c67-86f0-de64b87c45e3?ui=en-US&rs=en-US&ad=US), security groups can't be used to target the themes, however that's exactly what I'm using.

2) When creating a theme, I can "choose up up to five ‎Microsoft 365‎ groups" to see the custom theme - I've selected 6 security groups for one of them.

3) I was under the impression that these themes would also be used for the automated news digest email, however during testing they weren't applied to the emails.

Any clarification would be appreciated.

Cheers

 Rob