Mscott0566
Any advice on how to switch out the stock air cooler and replace it with a waterblock? My first time…

You're asking for an entire loop from scratch or just adding a GPU to an existing loop?  I get the impression you're underestimating what you need to do.

Yes I also was wondering. Does EVGA sell water blocks separately?

Mscott0566
Any advice on how to switch out the stock air cooler and replace it with a waterblock? My first time…

I dove into this topic myself.  And after an absurd expenditure of money and time, I have two fully waterblocked rtx3090's running in my loop along with the CPU.  It's really not hard at all.  But you should do extensive prep work and plan it out fully before buying parts.  I was so unorganized about it that I actually have a second machine running a small loop of it's own with another 3090ftw3 in it.  My use is mainly mining, but I also game from time to time.  My setup was done with function the main objective, form being little to no concern.  I attached a photo for simple reference.  Again, I had no concern over what it looked like, just that it worked as I wanted.  And ultimately it lowered the temp of the VRAM on both my 3090's to 78C while running vs before using extremely loud fans they were running about 86-88 C.
One thing I learned from the mistake of, is do not use ThermalTake products.  Absolute junk.  Pumps were loud and sounded like they are 100 years old.  Radiator leaked right out of the box.  Missing parts.  Basically they didn't get anything right.  I would recommend a Corsair preassembled it.  Cost you about $450-$500.  I am running the Corsair XR5 pump.  It is silent.  I can just hear the hum of the 7 fans in my system.