Hi,
First of all, thanks. Your suggestion of another browser prompted me to try Firefox, where the Asset Library worked like a charm, uploading maps instantly again. As Chrome and Microsoft Edge didn’t work in the initial post I didn’t try out another, but they are kind of similar these days I suppose.
Anyhow, I then wanted to report my Chrome version, which was 101.0.4951.67. It then prompted an update to 102.0.5005.63, which I tested and works fine again as well. So most likely the fault was with the 101 Chrome version and the one before it. Still odd, but hey, my problem is solved!
As for the Forge API error, I only uploaded via Foundry for troubleshooting. I actually don’t have the Forge module enabled by default, nor did I when testing, as I always upload via the Assets Library. Which is now possible again 