It depends, you can dose 2-3x a week still not run out of nutrients easily, this is done by knowing the max growth rate/uptake at high light, at less light, the plants will use less and they will have enough N, , K etc.
Yes, when plants get use to the stable environment, the tank becomes so predictable, dosing 3 times a week becomes sufficient. But stil the highest uptake is achieved by more frequent dosage.
This has some limits but you don't gain anything as far as the plants are concerned dosing daily vs 2-3x a week.
Right, plants are still happy.
Your habits might be troublesome(did I dose today? or yesterday or???)
No need to dose every day, you can skip no problem, this is not about keeping NO3 at 1 ppm. This allows to maintain any NO3

O4 ratio and any level. It's everybody's choice what to keep it at, 5.0:0.1 or 40:4. It's like a car running on a cruise control, you chose the speed and the gas keeps dosing.
but the plants don't care as long as nothing runs out or gets too low.
What element is not sufficient at low concentration?
It's not about cost, it's about time and enjoyment of a tank with water in it.
We don't feed fish 1 lb of flakes a day and then do water change to clean it up.
...you'll screw it up and stunt your plants the close you get to adding "Just enough".
Perpetual Preservation is not about Just enough, but about maintaining high levels of nutrients, full spectrum.
I know the ranges of these ratios, rather than some "specific" ratio. It's fairly wide ranging.
Plant uptake ratio is different at weekly dosing then at daily dosing.
You have changed your dosing from weekly do daily lately, days 1 3 5 and 2 4 6, why?
I am not sure what you mean by K+ deficiency, unless you have 75% of your N coming from fish food/waste, the KNO3 alone should be enough to supply the plant with K+, so the dosing of KNO3 will almost always result in excess K+ relative to the plant's needs.
A test by daily dosing of KNO3, KH2PO4 and K2SO4 showed higher NO3 and PO4 uptake then KNO3 and KH2PO4 dosed alone. The plants were able to uptake more nutrients with increased K. This was a Perpetual Preservation test that keeps stable levels. Surely K deficiency is not an issue with over fertilize and water change system.
Even a loaded Discus tank that's well fed did not need any K+ added using KNO3. 50% of the N came from fish waste.
The K test was done on a tank with no fish and a tank with low load fish. Same result.
I am not happy about the necessity of additional K, but the tanks were on hold with plenty of NO3 and PO4, going nowhere for two weeks. Small doses of K2SO4 made the NO3 and PO4 disappear.
Thank you for your time,
Edward