What are the specs of your old system?
Are you willing to reuse some parts?
The 13900K, Z790, and 4090 parts are as good as it gets.
On ram:
Games, by themselves will not use 16gb of ram. But, today, ram is relatively cheap so 32gb will keep any other tasks from interfering.
Today There is minimal performance difference between DDR4 and DDR5.
DDR5 motherboards will be a bit more expensive; 32gb of ram will cost about the same for either DDR5 or DDR4.
Unless you can reuse your old ram, the top budget you have suggests DDR5.
Intel does not depend on fast ram for performance. Do not overspend on ram.
The 4090 card is likely to require a top end power supply.
Probably 950w. Look for a quality unit with a 10 year warranty. Seasonic focus/prime or Corsair RMx is a good place to start.
If 2tb of ssd will suffice, buy a m.2 pcie ssd of that capacity.
You can always add storage later. Intel and Samsung make their own parts and I recommend them.
Do not be much swayed by vendor synthetic SSD benchmarks.
They are done with apps that push the SSD to it's maximum using queue lengths of 30 or so.
Most desktop users will do one or two things at a time, so they will see queue lengths of one or two.
What really counts is the response times, particularly for small random I/O. That is what the os does mostly.
For that, the response times of current SSD's are remarkably similar. And quick.
These experts could not tell the difference between slow and fast ssd's:
View: https://www.youtube.com/watch?v=4DKLA7w9eeA
A 13900K can get toasty if you can load all threads with a multi threaded batch app.
But for gaming, only a handful if threads will be actively used.
Here is an interesting article on running a 13900K with less than top end coolers:
The Core i9-13900K can push even the most capable liquid coolers to their limits, but you don’t lose that much performance if you go with budget-priced air cooling.
www.tomshardware.com
Unless you will be overclocking or are a competitive gamer, I suggest sticking with a top end air cooler like the noctua NH-D15 in a well ventilated case.