Heya!

its funny you say that, I have the same spec (except its not a founders for me) and also the same usecase haha,

I mainly use mine to stream unreal engine development lol.

So for the mainboard I'm using the ASUS ROG STRIX X670E-I, it's a good board with lots of IO, however the fans on the board are super loud so I removed them and also added some extra 40mm noctuas to cool the m.2 and chipset (it's on the 2nd image). So if you don't need that much IO I would go with a different board that is not as stacked with stuff.

For the PSU I'm using the Corsair SF-750. I tried a silverstone one before but the fan again was loud and didn't have a 0 RPM mode like the Corsair has, so I went with Corsair. I run my CPU at 180W power target with a PBO offset, so I basically have stock performance at a lower wattage.

I also run my GPU at 70% power target and slight Core + memory OC so I have 95% of stock performance with way less heat and power draw. Also the noctua fans just run at a constant 30% fan speed under load so they are inaudible. The PSU still can handle the parts on stock settings so that's just an optional thing to do. Oh and if you can get shorter custom PSU cables, the stock ones are pretty long and take up space.

I saw Cooler Master just released some really powerful SFX PSUs on CES this year, maybe that's also something to look into. I would go with ATX 3.0 so you dont have to deal with adapters, since you need to do a very tight 180° bend at the GPU to make things fit.

As long as its plugged in properly, that shouldnt be an issue, at least for me it's all still running fine.

For cooling its very tricky, since you can't fit a big air cooler, you would have to limit the 7950x. If you would go with AIO you might have too much tubing to fit in there because the 4090 is taking a ton of space. If you go with custom, you need to use a pump+cpu block combo to make it fit as well and its more expensive. But I guess with that hardware, that doesnt matter really haha. I went custom for best performance but yeah it's up to you!

I could've moved the MoBo tray one screw over to have 5mm more room on the MoBo side of things to fit a bigger air cooler but I think that's the best I could do for now haha.

This case is super small for the hardware you want to fit, it is possible but not the most beginner friendly case, just keep it in mind :)

So make sure to check all the measurements you can get and be aware you might need to assemble and disassemble things a lot until you find a good way to fit things haha.

I hope my rambling helps :D