Sooo, this got me thinking. Can I trick it into submission and let me order through the web interface? Short answer: yes!
I messed around with the Network Inspector and tried making various changes in the HTTP requests being made to the API by the web interface. After 10 minutes I found out that if you skip a certain query parameter for one of the crucial endpoints, but keep other ones unchanged, the API ignores this artificial geo-block.
4/
(I'm not going to share the particular details on which request and which query parameter that is)
So, after some changes, this is what I see on the desktop web. I can actually order a ride!
5/