I will just link you to this article, it is based on American prices, but maybe it can help you. The econobox and sweet spot would probably be where you want to look, and make sure to read the alternate parts at the bottom of each page.
Thank you very much for this, it's very helpful
You forget the SSD disk! It's really important, you have to install windows on the SSD and then your computer will start up so much faster with it. Use a 256 GB sized one (because such a big one is faster than the smaller ones).
Also, buy a big cooler with a big fan, to reduce noise (it looks like your system will need a lot of cooling). If you use the (small and cheap) stock cooler, and your system is running at full speed, then your computer will probably sound like a small vacuum cleaner. You will need a big computer casing of course, otherwise the cooler won't fit.
Start up speeds are not an issue if the computer is going to be left on for prolonged periods of time, it never gets switched off unless the power cuts, and is only restarted to install updates. I don't need a SSD