High altitude tourism in China nowadays is often supported with oxygen canisters. I have tried them with my son when we visited Western Sichuan. They seem to work pretty well, but they don’t last. Even by puffing sparingly every few minutes, one canister will not last a day.
Diamox is usually the drug of choice for preventing AMS, but over the years, the number of reputable/reliable sources for this drug has dwindled. Many of the tablets found in shops in Kathmandu are probably fake as I find them ineffective. The only effective Diamox tablets I last found was this bottle from New Zealand.
The next best thing could be herbal supplements. However, it is very difficult to conduct controlled studies for herbal supplements that purportedly help prevent Acute Mountain Sickness. Below are the three with the most anecdotal “evidence”.

Coenzyme Q10 is an energy-generating catalyst. It is not an essential part of the diet as the body is able to produce it. However, reduced levels are Q10 are found in individuals on long-term medication for high blood pressure and high cholesterol. Q10 probably doesn’t increase your energy levels but it can act as an antioxidant.

There is some TCM literature on the use of ginseng in treating altitude sickness. The herb is believed to enhance energy levels. Belonging to the Earth element, ginseng also nourishes the lung which belongs to the Metal element. Chinese physicians believe that ginseng is a powerful mover of qi and blood.

As the process of acclimatisation progresses, the individual’s blood thickens. Gingko has a blood-thinning effect and this appears to help with blood flow. I have tried gingko before. It’s no miracle cure, but it does give you a slight boost at high altitudes.
As with drugs, herbs cannot be guaranteed for efficacy. Different batches of herbs from different sources can have very different effects. Manufacturing inconsistencies can also affect treatment outcomes. I’m now in the process of experimenting with various sources. Hopefully, I can come up with my own product which I can proudly endorse.