Hi - I notice you are rejecting some high quality UK maps (Gainsborough, Strathshire for example) that are hosted on very respected UK OMSI site FellowsFilm. This will cause you to lose UK customers who will be forced to drive these maps outside of Bus Company Simulator. Maybe you need a different financial model? How about Sponsored Maps where customers pay an additional sum to help fund the cost of putting the map onto Bus Company Simulator / OmniNav ? Or leased maps where customers pay a monthly fee (say via Patreon or similar) to enjoy a greater range of maps?
The problem with your current financial model is that once customer has paid for Bus Company Simulator you are getting no additional sales revenue but being asked to do work to add maps.