If you're using a single GPU, that should be plenty. If you have a high quality PSU, then you could probably get by with less. I'm using a nearly 10 year old EarthWatts 750W, which is 80 PLUS Certified. A second GPU will have the lion's share of impact on your PSU. Check out this newegg tool: https://www.newegg.com/tools/power-supply-calculator/

Hello D, Thank you for contacting us in regards to your question. Yes the integrated graphics card from the Ryzen 5 3400G would work with this X570 motherboard. Fun fact is Ryzen 1000 series does not have a G series for integrated graphics. So technically the Ryzen 2000G series would be "1st gen" and Ryzen 3000G series is "2nd gen" CPU that supports Radeon Vega graphics. Hope this clarify somethings. Thank you and have a nice day! Newegg Support

Hello, The height clearance from the pins of a GPU to where the shroud normally starts is about a little less than an inch, so the SSD might be a little too close for comfort (especially with a heatsink attached). As far as airflow and thermals go, I think as long as you have good intake airflow from the front of your case, it should be enough to passively cool the SSD. With that being said, you might also get some passive heat from the GPU because of how close it is to the M.2 slot, but I think monitoring the temps yourself will give you a better idea of how well it performs as well as how