I am not up on the current prices of cards.
Dimension wise it will fit the case from earlier (max 390mm where
https://www.asus.com/uk/motherboards-components/graphics-cards/dual/dual-rtx2060-o6g-evo/techspec/ says 242mm long).
Cooling should be handled by the card itself. We can get into the weeds with case air flow but as long as there is air going in and getting drawn out by the case fans (I have seen people push air from all fans into the case before) and the graphics card fans are not blocked by a bunch of cables then you are probably going to be OK for normal gaming use (overclocking might be more tricky). If you want to get fancier and you are not going for some kind of positive pressure setup then the back of the case will likely feature a mounting point for a fan that would serve to blow air near to the GPU.
RAM wise I believe we covered that above. Outside of specific needs (usually high end video editing, some aspects of database work and high end CAD work) I am not sold on the rush to 32 gigs of RAM if the same money could go on making something else better. 24 should be fine, though depending upon how you do it you might end up sub optimal for what the motherboard expects/wants for peak performance (do also read the manual and see what slots you want to put it in -- while if it fits it will run is probably a thing it will run faster if put in the right slots to complete each other, 24 gigs tending to be the combination of 3 sticks or worse then possibly making some things run slower).
The one you linked should be compatible but might be overkill -- that says 3200 for speed where the link earlier says
"4 x DIMM, Max. 128GB, DDR4 2933/2800/2666/2400/2133 MHz Non-ECC, Un-buffered Memory" so it might end up running at 2933MHz unless there has been an update or something to unlock greater speeds (doubtful in this instance).
https://www.asus.com/Motherboards-Components/Motherboards/PRIME/PRIME-B460M-A/HelpDesk_CPU/ would say it is compatible as well, albeit at the slower speed. My greater concern was the voltage listed as sometimes there have been differences there, though usually more in laptops.
As far as power supply then we are still waiting on knowing what you have in there (should be able to open the side panel and read it off the sticker). The link above says "Recommended PSU 500W" which is probably a bare minimum for what was put into your machine (smaller ones are for laptops and very low end office computers) if it was even vaguely hinted at being a gaming machine. Whether the supply is any good (most of the time bundled supplies with cases or prebuilt machines are bare minimum that is not going to blow up during warranty period) is a different matter.