Hi @Jsn and welcome.
I’ve not experienced “image loading process is so slow” even in Developer Mode with CSS/JS Minification off. Ideally, you’ll want your PHP memory_limit set to at least 2GB. I’ve found that this makes a huge difference. So, even when you have a High-Spec server, having the memory_limit to anything less has a high impact on performance because it sets a soft-limit.
See how that goes and let me know. Also, ensure that your Full Page Cache is enabled because that also can make your site grind to a halt.
To answer your other questions:
- I’m not entirely sure on optimum server configuration. For the most part, my Web Server Provider manages most of this.
- There are Magento’s Requirements
- I honestly don’t find Magento 2 slow, even in Developer Mode. I think Enterprise Licence is around $30,000 per year.
For further speed tips, checkout Why is Magento 2 so slow? 12 EASY Tips to make Magento 2 faster