There's a "World altitude correction" map to download under the "Maps and Resources" menu. Have you downloaded that?
OpenStreetMap community
Everything #OpenStreetMap related is welcome: software releases, showing of your work, questions about how to tag something, as long as it has to do with OpenStreetMap or OpenStreetMap-related software.
OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
Join OpenStreetMap and start mapping: https://www.openstreetmap.org.
There are many communication channels about OSM, many organized around a certain country or region. Discover them on https://openstreetmap.community
https://mapcomplete.org is an easy-to-use website to view, edit and add points (such as shops, restaurants and others)
https://learnosm.org/en/ has a lot of information for beginners too.
Ignore my last comment, I just had to wait a bit longer. It is working now, thank you so much!
You're welcome! I'm glad it helped
Do you know what this map actually does? I am wondering if it's a coincidence that when I set osmand up, I was at around those 45m of altitude, does it maybe assume altitude 0 when being set up without this map?
I don't actually know
I had not, I have now but nothing significant changed.
Is your GPS altitude correct?
I have no idea. Where could I see that other than in osmand?
Any GPS mapping app should have the option to show it, or use an app like GPS Status.