Display sitewide posts with certain tags anywhere in the network?

Hello everyone!

I would like to display recent posts in a widget, filtered through given tags (inclusive, not exclusive filter).

What have I tried? I have searched for about 60 minutes and read through what I believe the following plugins can and cannot do:

- global-site-tags
- recent-custom-posts
- tag-feed (?)
- recent-global-posts-widget
- recent-global-posts-feed
(- autoblog)

I also tried to set up some of them, especially the third and fourth.

After a feed is only available to an RSS reader (?) and the recent global posts do not allow selection by *tag*, does the current park of options offer a path for me?

Of course I could try a workaround with a custom post type in the recent custom posts plugin, but it would be a workaround.

Should I try to strip RSS information into an external recent sitewide posts plugin? But RSS would not work for already-tagged posts?

Has WPMUDEV built in the functions I look for and did I overlook them?

Please help me with your expertise to find a plugin or solution that does the job !

A great thank you for any short comment!

Yours,
Clemens

(p.s. of course, I have post indexer installed ...)