I believe this is something to be aware of and if this is something you don’t want use GOG instead. But in reality as long as Steam exists you will be able to download and play your games. If Steam ceases to exists then you will not be able to download them, but there will be ways to still play them, if you previously downloaded them. It is not like “owning” movies on Amazon (or just recently on the Playstation Store), where you always need to stream the movies.

Keep calm and contact support. They are responsive, nice and will help you. I had a very similar thing, if not exactly the same. They gave me instructions, some of them I already read online, some of them not. It felt hopeless and it went back and forth multiple time until it suddenly worked again. They really know their stuff. In the end it was something with the base OS version.

I would definitely recommend to try it out right now. I‘ve never encountered any bugs and it is very polished overall. I think the only things that are unfinished are some story campaign scenarios, but there are enough in different difficulties to keep you busy for quite some time.

PS: It works great on Steam Deck!

Everyone who played and loved “The Settler 2” should give this a try. It has even more depth and removed a lot of the quirks like managing the stationing of trained soldiers.