If you are buying a car I would suggest tires and maybe a seat.
 
Seriously tho, maybe provide some input on what you intend on purchasing or your budget.  Intel? AMD? so many factors please provide more details on what kind of sandwich you want to eat.

for the cpu, AMD zen 2 (ryzen 7 3700x or 5 3600) in my opinion the 5000 series does not have that improvement that is expected in comparison to the price .. they consume little and do not heat;)

Nobody can recommend you parts if you don't include a budget. So, how much money you got?

I'd recommend a case, motherboard, psu, a cpu, some ram and some storage of some kind.    *sigh*

Majorpain100
I will be spending 2500-3000

If you're spending that much why are you going 3070Ti? I mean you can go on ebay right now and buy an EVGA 3080Ti XC3 or FTW3 for under $1900, so if you were spending 3 grand (assuming US dollars), you have enough to pair it with a 11900K, a top-tier motherboard, 32GBs of DDR4000+ RAM, a 1000W PSU, 2TB NVMe with additional storage if needed, case and then CPU cooler, fans and remaining smaller parts.
 
You could also build a crazy custom loop.
 
 

Parts you're gonna need:
 
CPU
RAM
STORAGE (NVMe recommended)
PC Case
PSU
Keyboard
Mouse
Desk
 
That should get you going.

3070ti is not a good choice, it is more like the positioning of 3070 super

When it comes to performance per price ratio, the 3070ti is terrible, either find a 3070 or spend a little extra for a 3080.
 
Besides basic components required and mentioned above, you wouldn't want to game on a 1080p monitor to waste its potential.
 
You must consider if there is also room to improve your display monitor. The visual experience is equally important.

power supply?

wait for the 12 gen cpu from Intel at end of year.