ASUS disagrees and said only an AIO would be sufficient (perhaps because they don't sell tower coolers?), and said I should get at least the Ryujin II 360, so I continue to solicit knowledge about AIOs, for those who are knowledgeable about them.
Oh Asus... hahahah... if it guarantees a sale, of course they'd say that.
Their Ryujin II is 'meh' on performance. For as much as it costs, the thing isn't breaking any records(except cost). Asus shot themselves in the knee using NF-F12s, which aren't actually that good on radiators.
I've got several F12s - the regular and IPPC 3000 - so personal experience is involved, then there's this TPU review of them that came to the same conclusion:
https://www.techpowerup.com/review/noctua-nf-f12-pwm-chromax/5.html
'Only an AIO/CLC is sufficient'... BULL... and no, they don't sell air coolers.
With one exception, the performance gap between tower air and AIO/CLCs is negligible to small in practice, and it is 'our fault' for that outcome. I do not suggest adopting liquid for performance alone.
NH-D15S, Silver Arrow IB-E Extreme, True Spirit 140 Power, Celsius S36, Celsius+ S28, Eisbaer Aurora 360(Phanteks T30-120)... < all coolers I've used, or am currently using, and what I've gathered through those is that:
Our ears are what allow air coolers to stay competitive with the liquid ones - or I twist it around and say: Our ears keep the liquid coolers from completely wiping the floor with air coolers... though there's that one exception which I haven't stated yet.
The fan(s) that come with AIO/CLC typically have higher max parameters(CFM, SP, dBA) than those on air coolers, but for good reason: the extra air resistance presented by the radiator and case panel the rad is installed against.
Though that reason is for naught due to more noise = bad/unwanted.
An air cooler's fan(s) exist for itself, whereas those on AIO/CLC is for both it and the components inside the PC - in other words, they're both cpu/gpu cooler AND case fans.
If you've seen noise normalized performance reviews... those are close to what I suspect most will run the fans at, but some likely still find that too audible, and either lower fan speed further(which doesn't help the 'reason' mentioned earlier), or replace the fans($$$).
To sum this little paragraph up: AIO/CLC fans usually aren't as well balanced as those of air coolers, due to trying to play 2 roles at the same time.
AIO/CLCs are more expensive than the retail price suggests(it's deceptive).
If one has deep pockets, I figure it's no big deal. For those on a tighter budget, they may not be a great first pick.
If one uses their PC for work, and 'time is money', then I strongly suggest having a backup cooler on hand for when the pump fails, or even shows signs of trouble.
These coolers are convenient for cases that come with no fans or just 1-2, so they've got that going for them.
Some folks talk about air coolers being big and blocky, but AIO/CLCs are air coolers stretched way the heck out and with more fluid in them.
"Do you want the air cooler focused in one area, or do you want the air cooler running from Point A to Point B to Point C?" XD
Oh, and that exception where air coolers can't hang with liquid: all core load, high power use during said load, and run for extended periods of time. That's when the gap can get large.