Huh, how did I miss that?! I know that sign is the difference between circular roads and roundabouts, so I must have specifically looked for it and not seen it somehow

Thanks for noticing my mistake so quickly! Feel free to just revert in the future, if you have the time

The highway=mini_roundabout tag you mentioned looks fitting, but the wiki says that it mustn't be used on a way. I've mapped the crossing as a node now and added this tag, since several examples I looked at on the wiki seem to confirm that this is the only right tag for this situation. Thanks again!

https://osm.org/changeset/172889976