What computer to build?

Question

Computers

I am planning to buy a new home computer due to the physical obsolescence of the laptop in 2011 (Acer Aspire 5750g).
Tell me, please, good options from your experience, who really tried what, or maybe friends use it. I know that there are all sorts of assembly constructors, for example, in DNS or Citylink, but I would like to hear your opinion. I plan to buy in parts and assemble it myself. Thank you.

Requirements:
1. Must support connection of 3 monitors via digital connectors (not VGA). This is convenient for comfortable coding.
2. RAM. At the first stage, there should be 32 GB, purely for comfortable work. The motherboard must support expansion up to 64 GB if necessary.
3. Video card. I don't play games - once in 5 years in GTA or DotA 2 it doesn't count. But, if you ever have free time and want to play, let the computer pull Dota 2 at maximum speed. Sometimes I work with video (purely a hobby, not a job) at an amateur level in VideoPad. I think the video card is mainly needed here to pull three monitors normally.
4. By hard drive. There is nothing special to store, let it be 1TB in total. For everything else, there are removable hard drives and a hub. I don’t particularly understand whether it is necessary to put an SSD on a home computer or an HDD is enough.
5. I would like the most compact case that could be hung on a bracket under the countertop. Not a supporter of the system unit standing on the floor or on the table.
6. 2.4/5GHz wireless network adapter. Gigabit Ethernet port. Bluetooth module is good. Just in case, standard 3.5mm inputs for audio and microphone. Let there be at least 4 USB ports.
7. There will be two operational systems on board. Windows for work. Ubuntu for leisure.
8. Budget: up to 80-100k rubles.
PS: Motherboard and processor - somehow it doesn't matter, only requirements 1-7 were met.

UPD 07/10/2021: The computer assembled, described its assembly in the answer below.

Answer 1

roughly threw, but without a guide to the price of the
mother - https://www.dns-shop.ru/product/6d3e51509bd41b80/m...
stone - https://www.dns-shop.ru/product/4607168e6a693332/p. ..
memory 2 bars https://www.dns-shop.ru/product/ea72cd89accf3332/o...
vidyaha - https://www.dns-shop.ru/product/1cb661c7f0263332/v...
bp - https ://www.dns-shop.ru/product/d823456e919d3361/b...
housing - https://www.dns-shop.ru/product/022f826530bc3330/k...
cooling - https://www.dns -shop.ru/product/0b1f9b12b9e13330/k...
76400 rubles
https://www.dns-shop.ru/product/871f7675472f3330/1... zhd +3700
ssdhttps://www.dns-shop.ru/product/53ce8c9f1ea93332/2... +4700
cooling is questionable, you need to look to get into the case, but not the gammamax that everyone molds