To build that system yourself is about $1350 Euro with brand name components, they use PC Specialist which would be their generic brand and cuts costs for them
So you're paying roughly $350 for build, etc
Like
said, as long as you're happy with it that's all that really matters
https://de.pcpartpicker.com/list/zgDfk9and anything 11th gen or higher should be running an NVME PCIE 4.0 to maximize performance
https://de.pcpartpicker.com/list/zgDfk9GL