Cheapest case and PSU in the EU

Hello, I just bought a BC 250 today and an NVNE ssd on AliExpress. I have been looking a bit around but I am not finding a good place where to find cases and power supplies that are easy and cheap to get in the EU. I don't have a 3D printer and i absolutely don't want to have a jet engine in the living room, I would like to make this as quiet as possible.

I have seen that it's possible to unlock 2 cores and the full 40CUs but I have not found much about the excess consumption and how to handle things.

Ideally I think I would like something that can be fully silent when around 100-150w and be still acceptable when at full load which I guess would be around 250-300w?

I'm mainly looking at pointers where I can learn more about it and understand what is the best way to handle this.