I would say raspberry pi 5. cheap, small and widely used so much of the stuff is already done many times

Looking at Raspberry Pi prices inside EU, I can get 8 core laptops for a cheaper price, with display, dGPU et al.

No idea what happened, but Raspberry Pis are super expensive for the last couple years, which is why I decided to just go with used Intel NUCs instead. They cost around 80-150EUR and they use more electricity but they are a quite good bang for the buck, and some variants also have 3x HDMI or Gbit/s ethernet or m2 slots you can use to have a SATA RAID in them.

Same.. switched over during the pandemic when full on N95/100 systems were cheaper than just the RPi board by itself. More compute/ram, faster storage, included case and power, fewer headaches.

Is it better than a n100 setup from China? When you factor in the storage, power supply, case, (fan), and so on?

No. The main pain point with RPi's is that they're SD card based – which are slow and prone to failure. Configuring an SSD to be used as the main storage has also been a pain in the past (not sure if that's changed recently).

With an n100, you get a better, more upgradable system for around the same price and same power usage. On top, you will also have an x64 system that isn't limited to some ARM quirks. I made the switch n100's over a year ago and have had no issues with them so far.