* Tax monopolies more heavily and redistribute that money in the same area. Take from Google, and give it to competitors like DDG, even Bing, and even back into Google.
* Heavily socialize basic things like transport, telecommunications and education. These are things that help foster growth from independent sources.
* The environmental issue is tricky. I don't think it's possible to deal with until things get really bad, at which point it'll be quite late. Hopefully not to the point where we go extinct (unlikely) but probably where millions will die (directly or indirectly). Until then, I don't know if there's much that can be done.
For (2) advanced economies are becoming more service heavy rather than production heavy. Many services are less location-dependent than goods production and therefore money can flow to more locales. (e.g. I know a few folks who are programmers + small scale farmers)
And (3) is hopefully becoming more important as the scale of the externalities increase (e.g. Chinese pollution hurts the whole world, not just China).
They seem to be good at 1) long-term thinking, investing all around the world and building infrastructure 2) preventing people from moving out to big cities away from their birthplace 3) seem to be interested in addressing pollution externalities, building nuclear energy power plants fast.
They are still a massive polluter, so they are not perfect, and the political system is probably not a western liberal ideal, but we can and should learn from them.
The better capitalism will probably be less of capitalism and oligarchy, and more of a powerful social democracy state.
For #2, I think this problem exists globally. Money moves around, a lot. You can see it at the national level via trade surpluses or deficits. I'm not sure anything will really change that (other types of political structures have the issue, and many tariffs don't produce the intended results.
Regarding #3, everything has externalities. I don't actually see much being truly done for these issues - it shifts from one thing to another. The main way to reduce externalities is to reduce consumption, but I don't really see that happening. For example, EVs release less CO2, but still use rubber, the electric can come from coal, the lithium causes environmental issues in places like Chile. Is it a step in the right direction? I think so. Is the benefit really as good as its hyped up to be? I think not.
2. I’m not sure that’s a problem.
3. Pollution is vandalism. Treat it as such, using fines or taxes.
The economics articles that I've read generally suggest that you need laws and taxes that work against its excesses - workers' rights, environmental protection, consumer protection etc. These should be capable of being amended to address new problems as they arrive.
Regulation and taxation are rarely popular things on this corner of the internet but they're useful tools to tackle some hard problems.
One question is - what has improved under capitalism? That children don't have to go to dangerous, Dickensian factories is one improvement. Between labor agitation and capitalists realizing a literate population was more profitable, this changed in industrialized countries.
So, one way of improving it would be the widespread adoption of minimalism as a value. This seemed to be happening a few years ago with Marie Kondo et al., but I'm not sure if it has maintained momentum. Of course, it's also antithetical to the way Western capitalist economies are set up, so in the short term, a turn toward more digital consumption and less physical consumption might be helpful.
So one very important way to improve capitalism is to break up monopolies and oligopolies much earlier and drastically than it is done nowadays. This is even more important in IT, with its winner-takes-it-all-market.
100% recycle:
Remove unpaid externalities. Price in everything down to the exhaust and the packaging. Every manufacturer needs to be responsible for all of what they sell, make sure its all recyclable/reclaimable.
True responsibility:
Make CO level suite leaders personally responsible when they mess up big enough. Mostly in terms of negligence and loss of life. Things like Bhopal, heads should roll.
Firewall between politics and money:
Nothing's going to work if the people running it can be bribed (or any other similar term). Have an election? Here's a pool of tax money and advertisers have to provide discounted time and space.