skeltalcomrade

The 3000g is still based on Zen or Zen+ (i forget now which one and can't be bothered to look it up) , it's not a Ryzen 3xxx processor, so it should work on older boards without bios updates (or at least the boards should boot with it).
 

For 3rd gen Ryzen yes, but the 3000G is zen+ so I am not sure if it requires the latest bios or not. Most likely the vendor will make sure it's compatible, contact them to inquire. However, I believe both boards support USB Bios Flashback so if needed you can do the bios update yourself. 

It's a 3000G. Don't bother with the tier list.
Just get the cheapest B450 board you can find and off you go.
 
ITX boards in general are very rarely garbage anyways because they are designed to work in hotter ambient air than other motherboards.

Yeah people get overly critical about the ITX boards and which to get and to not get, any B450 ITX board is gonna be decent. It's like choosing your favorite carbonated beverage, it doesn't matter, and nobody else cares. 
 
Get this:
https://pcpartpicker.com/product/ZGDJ7P/gigabyte-b450-i-aorus-pro-wifi-mini-itx-am4-motherboard-b450-i-aorus-pro-wifi
OR this:
https://pcpartpicker.com/product/gBWfrH/msi-b450i-gaming-plus-ac-mini-itx-am4-motherboard-b450i-gaming-plus-ac
Both are solid.
 
You are limited on fans anyways, this goes for any HTPC or ITX case. One for intake and one for exhaust is good. In my SG13 I use the 120mm AIO as intake and have one single 80mm fan exhausting the hot air.

thanks