My Home Assistant is installed on an HP Pavillion Mini 300 , in which I installed a used SSD and it works great. The HP Mini PC is available on Ebay for just under €100, making it cheaper than a well-equipped Raspberry Pi. And with a power consumption of 7 W, the Mini PC is not very energy-hungry either. An Intel NUC or any mini PC will probably work well too. If you want long-term evaluations of your data, you should use an SSD.
A Raspberry would certainly also work, but I’ve often read that a Raspberry reaches its limits with larger Home Assistant systems.
I installed Home Assistant directly on the Mini PC according to the instructions .
So that I can continue to use my Homatic IP devices, I reused the SmartHome radio stick for Homematic IP from my old SmartHome solution and took a Bluetooth USB dongle for the Bluetooth devices.