For books an important features is that the shelves have doors and a back, to have to dust off the books less often. Do yours come with that? I'm not finding that brand on any Swedish retailer from a quick search either, so not sure how relevant it is.
I have some older Billy shelves that have been very solid, even when overloaded with books (I too have a lot of physical books, a lot of them older and not available as anything except physical, quite a few even predating the ISBN system).
Mine from that company so far are library-style open shelves. I have a vacuum attachment I like for cleaning shelves and books, so it doesn't require a feather duster. I keep certain books inside doors and backs.
The same company also makes cabinets and enclosed cases. They are available via a handful of retailers in the US. The big one is Amazon. I would have guessed they sell and ship worldwide since they're on Amazon. It appears I would have been wrong. I can't find the brand on the sites for Sweden, UK, or Germany. If I set my delivery to Sweden, I can't even find them on the US site by searching but can still see their store page. They don't seem to be on AliExpress either.
I have some older Billy shelves that have been very solid, even when overloaded with books (I too have a lot of physical books, a lot of them older and not available as anything except physical, quite a few even predating the ISBN system).