https://www.tomshardware.com/pc-components/air-cooling/thermalright-phantom-spirit-120-evo-review/
12th gen is already a few years old at this point, and its quite hard to find sls shops still selling it. getting a k cpu and a b series mobo also feels like a waste, since b series mobo cannot overclock and thus ur throwing money away for a feature on the cpu that u cannot use. u can also find cpu mb combos that are better for gaming and also cheaper. my go to right now is a ryzen 5 7500f and b650 for under $500 (though white amd mobos are very rare), so unless the 12600kf + b760 sl is significantly cheaper or a full white pc is a must i would go amd.
nzxt aios are generally overpriced for the level of performance on offer. i would only go for it if aesthetics are a priority, else i would just go for an arctic liquid freezer ii which delivers comparable cooling for a much lower price. or if u go amd as i suggested, u can settle on air cooling for even less like ones from thermalright as soreloser mentioned.
the price gap between the 77xt and 78xt is too little to justify the loss in performance and vram. just go for the 78xt unless ur budget is really that tight.
techyard has a very well priced kit of white 2x16gb 6400c32.
all of those cases have a psu shroud with no cutout, so no point spending extra on a white psu. if the adata xpg core reactor is still available around $120 from pckaki/perf pc, that would be ideal; otherwise an asus rog strix 750w for under $150 from pct is a decent deal too.
if ur budget is that tight, full white builds will come with too many compromises to be worth it imo, since white parts generally cost more for otherwise no functional difference.
sounds like a good idea, or u can see which shop u buying the most parts from, collect the parts not from that shop first then one shot buy and build at that shop.
case wise, ive left some recommendations at the bottom of the first post, though since it is not a very low power build, u could get away with a cheaper case.
i should note that i do not know if the 6650xt is still in stock, so if it is not, i suggest going for the rx7600 which can generally be found below 400.
u dont have to look overseas for these parts, dynacore has a decent price for 7500f + asus tuf gaming b650m-e which is only $20 more. the tuf board has a much more well rounded feature set, plus u get local warranty. and if im not mistaken, the aliexpress price is without gst, so with it added the overall price is about the same.
id get the newer better phantom spirit 120 se from pct for $51.
850w is very overkill for a 7500f + 4070s build, 550w enough. either the adata or asus psus as mentioned above in response to rain29 will be better picks as they offer double the warranty length (10y vs 5y for superflower) for a comparable if not cheaper price. and imo, going 7800xt is still the better pick as u can save almost $200 for 90% of the 4070s performance, plus u get more vram. so overall u can save quite a bit, plus u get all local parts with distro warranty if u follow the reco on the first post, with similar value when considering raster performance.