I thought the optimal configuration for sv590 is for the Rad Fans to exhaust air out of the case and let the air be sucked in from the side panel? That's what I'm doing.
This is correct - if the fans blow into the case they can cause problems with the PSU and GPU cooling.
If you're on a custom loop the GPU doesn't matter, but I'd be wary of torturing your PSU with high temps.
I'd also recommend putting the PSU fan towards the inside of the case to pull air from behind the GPU - made a few degrees GPU temperature improvement in my testing.
Waiting on news out of China on PCIe risers and power switches.
Honestly looks like they went back into lock down as I haven't heard anything today, cannot contact any of our vendors.
Might not be good.
If they do drag this lock down out we will probably go on backorder for existing cases, and put up a bunch of new preorder cases.
Have another 2-3 weeks before we have to start thinking more seriously about that.
Another question - do I have an issue when I use a WLAN adapter (2,4GHz) for my keyboard and gamepad? Maybe the case will disturb the connection/quality of the signal?
Without getting too technical, no you should not have any issues or signal degradation.
The only thing you could do wrong is if you have a higher gain (8dBi+) antenna that can be bent over and you fold it over so that your wireless AP or Keyboard/Gamepad are in the vertical dead zones. Best to go with a low gain (2-4dBi) stub antenna if you're in a smaller apartment, or an externally mounted mid gain (5-6dBi) if your AP is really far away such as a larger house or office.
Either of these should be viable work around at 2.4GHz if you want to play it safe, these look like best value on Amazon for respective purpose: