What I would like to find out is how I can hide this memberlist on a sharepoint folder. I would also like to hide it from showing up on the group emails.
They display be default and there is no OOB method to disable them.
In SharePoint Online modern experience, we need to use SharePoint Framework Extensions to add scripts to "modern" pages.
Check Information about Customizing the "modern" experiences in SharePoint Online
Another workaround, you could switch the experience from modern to classic. The members are not appeared in classic experience.