Hi,
I've found this layer 'OpenStreetMap Power Structures for Europe' which almost fulfills my requirements. But I can't figure out how to edit it or create my own layer based on that work, or from scratch.
What would be the process to create such a layer that includes the following tags from OSM?
You might take a look at https://osm2pgsql.org/ or https://imposm.org/, which can be used to easily pull specific features and attributes into a PostGIS database. The resulting database can be registered to a server and have services published from them, or you can use the database layers to publish a hosted copy to AGOL or something.
It may seem like a big task, but it's the best way to have full control over the process.