This is pretty much exactly what I've been looking for.
The only thing missing would be a way to interact with the Items from the inventory-screen.
Any idea how one could whip that up?
Viewing post in Simple Renpy Inventory System comments
The simple inventory system is intentionally designed to be straightforward, avoiding unnecessary complexity for beginners. While it could have had more advanced features, I kept it minimal. For something more advanced, you can use my Enhanced Inventory, though you’ll need to add image buttons to the loop in the screen code to trigger actions that open another screen. It’s fairly easy, but adding the image button can be tricky if you’re not familiar with the engine.
Another option is my upcoming complete inventory system, designed to cover every edge case for game developers across all genres, from dating sims to RPGs. This ultimate version includes everything you can imagine, built from years of collected feedback and featuring AAA-quality elements. However, it’s still in beta testing, so the release will take a little more time.