My understanding of COPD is lung tightness and not producing phlegm.

So in the Netherlands, they found vitamin K2-MK7 can help with lung tightness
https://www.cambridge.org/core/journals/british-journal-of-n...

Whats not liked about this study is its sponsored by a company that makes K2-MK7 aka Kappa Bioscience. Personally Kappa should have used K1 in powder form, injecting vitamin K is a big no no like most things designed to be consumed orally!

So K1 is probably the best form to take 50mg will see your lungs relax or reduce tightness within 30mins. K2-MK4 is best for directing the calcium to the bones so whilst you can use 20mg of K2-MK4 as a sleeping pill in hard water (calcium rich) area's its taking the calcium out of the blood stream so calcium cant bind with adrenaline, because when they do, combined they have an even greater stimulating effect. The longer K2-MKx chains can be reduced down into short K2-MKx eg K2-MK7 can be reduced down to K2-MK4, and K1 is converted into K2-MK4 when its been through the Rough Endoplasmic Reticulum, so to keep calcium out of the blood stream and direct it to the bones use K2-MK4, to keep clacium out of tissue like elastic fibre's in lungs use K1. A combination of the both wont do any harm either, but K2-MK4 I would only take just before bed as it can help keep you very relaxed during the day and possibly could be used a mild sedative for highly strung people!

Choline (bitartrate/(CDP/citi)choline) lowers the pressure in the alveoli so the gas exchange takes place more easily, so your CO2 can escape and O bee absorbed more easily.

N Acetyl Cysteine helps the metallothionein so MgSOD in particular but also Cu/ZSOD (Super Oxide Dismutase) can help alleviate inflammation in the lungs which will reduce the excessive destruction of surrounding "healthy" cells caused by the immune system. We cant orally absorb L-Cysteine easily, but NAC we can absorb nearly 100% of. 1gram can see phlegm production and a mild reduction in lung tightness within 30mins even when smokers lungs are no longer "productive" ie chucking out phlegm.

Histidine precursor for histamine which helps white blood cells move through tissue, can also help reduce inflammation.

Increasing copper above the former 2mg RDA can help with Cu/ZSOD and copper will help increase Interleukin-2 which is one of the things used in chemo, although I note the science suggesting its best injected into tumours whilst ignoring the fact that penicillin based antibiotics help reduce copper in the body when its metabolised into penicillamine used for copper toxicity and Wilson's Disease. Not helped by Copper RDA being reduced from 2mg to below 1mg recently, perhaps the Cancer industry is extremely lucrative!

Iron in state 2 ie ferrous iron in low gram amounts for short term 1-2weeks can also help increase myoglobin which stores, iron, oxygen and Carbon Monoxide in the muscles, this can also help reduces panic in people. An enzyme in the gut which absorbs Iron Oxide (ferric or state3 iron) is rather limited, but an excess of ferrous iron can see iron diabetes and increase the chance of spontaneous internal haemorrhaging which is why new borns get a vit K shot instead of giving the mother vit K supplements at the first signs of the birth.

I'm not qualified in nothing (one up from living on the street) so this is just my opinion as curriculum's and examinations are political agenda's.