Just basic setup, thinking i5-10400 (or equivalent.) 16 or 32 gb ram, already have a new 1050ti 4gb. Some sort of ssd, nvme maybe. Also already have new Corsair CX650 as well.
Very reasonable. For just gaming, 2 x 8gb should be ok for gaming. More does not hurt, but there is little value unless you are also multitasking.
On ram speed, it does make a difference, but mostly for integrated graphics.
The motherboard will be the main determinant.
I find that "future proofing" is not very effective.
Most upgrades for gamers will be for graphics cards, and the 650w psu will be the limiter for that.
Here is a handy chart for gpu upgrades:
http://www.realhardtechx.com/index_archivos/Page362.htm
It is multiplayer games with many participants where many threads help.
For single player, it is hard to (effectively) use more than about 6 threads.
Games such as sims, mmo and strategy games are the ones that depend most on a fast single master thread.
You can see the performance characteristics of processors by looking at the passmark performance numbers.
For example, the i5-10400 has 12 threads and a passmark rating of 12357. That is when all 12 threads are fully busy. The single thread rating is 2593.
https://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i5-10400+@+2.90GHz&id=3737
The 11th gen processors have some 19% improved performance per clock compared to 10th gen.
The i5-11400 mentioned above is excellent, with 12 threads and a rating of 17319/3051.