First rule i would recommend is to never take shop listings as face value, and take time to look at product page and/or manual. In your example, you would go to https://www.msi.com/Motherboard/MPG-X570-GAMING-PRO-CARBON-WIFI, go to Specification and then Detail.
And then you would see this in...
Well, your best bet would be https://www.asus.com/Motherboards-Components/Motherboards/All-series/Pro-WS-X570-ACE/ which has three PCI-E 4.0 x8 slots (bottom being connected to X570 chipset, which has a PCI-E 4.0 x4 uplink to CPU). But pricing in US/CA is insane for this board for some reason...
GPU power usage is peaking around 300W for a decade by now, also going to smaller node size usually means decreased voltage. There are also physical limits to how big GPUs can be, so the coolers you see now is probably the peak size you will see until GPUs change their form factor completely.
Power usage increased. Radeon 9700 was 37W TDP. 8800GT was 125W TDP. Current cards are usually between 150 and 300W TDP.
Also people prefer quieter cards.
Both of those factors require bigger coolers, which can be cooled quieter and/or can keep a GPU with higher TDP at reasonable temperatures.
Depending on memory chip and module design, it might still be needed. It is all about the strain the specific modules put on the memory controller. Trying to bump the SOC voltage for a while won't hurt anything anywya.
It might be just not enough SOC Voltage for the memory controller; for my 4x16GB DDR4-3200 config i had to increase the voltage to 1.15V to consistently make it boot, otherwise it would stop posting sometimes.
For Ryzen 3600, literally any AM4 board will do (well, i wouldn't buy A320, but other than that).
And then it comes down to required feature set.
X series boards will have x8/x8 bifurcation of the x16 CPU PCI-E lanes, B450 doesn't have that. But if you run single GPU, it is irrelevant.
X570 has...
National governments, EU parliament and EU commission have different responsibilities. If anything, "trafficking" is an issue for each national government, each national police and Europol - EU is not United States of Europe, it is not job of EU to solve criminal issues.
EU commission and...
Do you require mATX ? For mITX, there is Silverstone DS380:
https://www.silverstonetek.com/product.php?pid=452
For mATX, there is CS381, but it is rather big:
https://www.silverstonetek.com/product.php?pid=861&area=en
For Full ATX, there is CS380...
You might laugh, but you are not that far off. For higher current charging to work, various manufacturers required various voltage levels on data pins https://obddiag.net/usb-power.html . So while any charger will do the 5V/0.5A charging, anything above it was manufacturer/feature specific.
And...
Well, if anything, SKU should have rang the bell. EVGA SKU for that card is 06G-P4-1267-KR ( https://www.evga.com/products/product.aspx?pn=06G-P4-1267-KR ). And that SKU scheme is old as hell at EVGA, for example their old GTX260's had 896-P3-1270-AR - so as you can see, their SKU is always...