Add "Anyone with the link" as a sharing option.
It can be useful to host images and files directly in AGOL that can be referenced by other AGOL products like map popups, apps, and experiences. The way sharing works now in AGOL you can set the sharing level to "Owner", "Organization", "Public", or "Groups" like the image below.
Today modern file sharing solutions allow for an "Anyone with the link" option. This option can be useful in cases where you don't want files searchable by the public, but you do want the files publicly accessible. This gives you greater control over the context users see when they access to your files. Access to this setting should be controlled by the organization and based on the user role.
In my use case it would allow me to prevent anyone from accessing graphics or map symbol images that I'm hosting on AGOL for use in a popup from finding them through searching AGOL.
@asimmons have you explored adding those members to a group, sharing the item with them, short URL or share links options?
There's some information on sharing links in this documentation that may be helpful.