The search APIs we use do not support specifying "EU" as a whole. What you see in our region picker is what we get to choose from on our end, which is down to country/regional granularity; there is no in-between.
This would require either our own full scale indexes in order to provide this ourselves, or getting every (or at least 2) source we use to agree to adding support for this for our use case. So in terms of this happening as-described in the near term are slim to none.
The best recommendation we can make is to make domain ranking adjustments and create lenses for specific use cases (e.g. EU shopping) that filters on domains or TLDs to coax relevant results from our upstream indexes.