Get content of referenced fields in multiple value fields

Problem/Motivation

I'm using the metatags module and want to add a default value for the
opengraph standard for the image. The media field in my content type can have
unlimited values, not just one.

For a single value reference field I can use something like

[node:field_media_image:entity:*:url]

to get the url of the image.

But I cannot use this in the same way for multi-value reference fields, like

[node:field_media_image:0:entity:*:url]

This just seem to get ignored.

Am I missing something or why isn't this possible?

Thanks in advance.