Nope, I just used to have my system files on the 250GB SSD and other things on HDDs until I recently bought the 1TB SSD
from my understanding it's pretty typical that gen 3 ryzen CPUs run somewhere between 50-60 c on idle
The glass panel is pretty dark, I'm not sure what kind of lighting would be enough. I don't have led lights inside the case besides what the has MOBO.
As far as I know the NAVI cards are on par with RTX lineup in terms of power consumption relative to performance. Having said that, as you said it can be hard to find the custom 5700s for a competitive price (especially in EU, this is why I ended up purchasing Nvidia).
From what I learned doing my research, the b450m is a quality mobo, and I ran into no issues with building the setup from 0. Flashing the BIOS has a couple steps you need to follow but nothing difficult for sure. I was also off put by the x570 prices!
The GPU is older than the CPU and rest of the stuff, but I am eyeing a GPU upgrade for the future. There are a ton of options and things to consider, even the fact my secondary monitor only has DVI connection (adaptor adds a cost) and even power consumption (not sure if 620 watts is enough, say, for an RX 7500 XT). The fans were definitely a splurge, getting the Noctua fans just made me feel so good.
Hey, I forgot to write down I used the "flashback" feature of the mobo. For that you don't need any CPU. Sorry for the late reply.