If budget is a concern I recommend that you scourge the classified section and other fb buy/sell groups for used parts.
There were some parts which you required being sold here.
Some additions:
1. Buy RAM in dual-channel and get it at once. Don't buy 8GB now and 8GB later. Not going to be worth it and price difference shouldn't be much. Single ones cost more anyway. And stick to 3200MHz unless you can get the 3600MHz at the price of 3200MHz. Difference is negligible.
2. You may get a usable PSU in that 4k budget you specified but it may not be a very good one let alone 80+ Gold or Modular.
3. Dunno what to recommend for the CPU/GPU. Get the best bang for buck I guess. Again I recommend used parts. The Deepcool should be enough.
4. Don't let the PCI version get into your head. Latest ones are not ready for mainstream use.
5. Buy new good quality monitor. Used ones are very rare.
I've been keeping an eye on the classifieds section. However, the reason I want to get new is because I haven't touched a PC on almost 10 years and am not confident enough to assemble it myself. If I but from Lammington, they'll assemble it for me.
Budget is a concern to the extent that I can spend if I had to, I just don't want to go beyond 80k for a gaming PC.
I'll probably eventually go for 2x16 GB RAM. Games don't need that now, but 2 years down the line they might. And if DDR5 is common by then, then I'll have to pay more for DDR4. So better to get it now. As for 3600 vs 3200, there's practically no difference in price.
I might get a gold certified PSU for 5-5.5k, modular won't happen, yes.
For CPU, I'll pick between 12400F and Ryzen 5 5600 depending on what motherboard I find and what's the final price. Both are good enough for me.
GPU, I've decided to go with 3060. I read some reviews and it seems to be better than 6600XT overall.
I already have a monitor, not buying currently.