I’m still looking for a good app to identify insects (mostly in Europe). Is iNaturalist the best?

It is.

• good automatic id
• manual id by scientists or enthusiasts
• you develop your own Pokédex
• you provide data for scientific research

Also, if you put your image(s) under a compatible license (CC BY-SA or less restrictive), we on Wikipedia also pull from iNaturalist for images to add to Wikimedia Commons. It helps a surprising amount.