Even if you could solve the hardest problem, you still need to eat while working on it. This means that one of the most important problems to solve is more efficient basics. 500 years ago 95% of the world males were farmers (maybe enslaved, but still farmer). Women had to spend 10 hours per day making clothing. (Historians can give better numbers and details of the sex difference, but for this discussion the above is close enough despite missing many details)

Making the basics more efficient is always helpful. Though this is hard as a lot of smart people are already on the job.

Your ego should slightly overshoot your ability.

or what's a 360° feedback performance review for?

I think an issue people have is they believe they are good at solving problems which they then think they can do minimal research on something and will be able to solve problems in that domain.

I've spent my career building web based software for solving business problems. That doesn't translate at all to solving anything that qualifies as a problem for the world or humanity. I don't intend on changing my career trajectory at this point, I'm fine with solving these types of problems for the money it pays. This doesn't mean I don't care about big/important problems just that my contributions to those will be small in nature based on my personal time/money.

i feel that the highest impact comes from efforts that have a long term effect. one of these is to change the attitude everyone takes towards the world.

what the world needs the most is more people who understand that we all need to make an effort and contribute to make things better for everyone.

to get people to reach this understanding and be serious about it and also feel like they can actually have an impact, and more importantly have the hope that it will work and is not futile takes living by example and impress that on your family, friends and neighbors. then as your resources allow engage in the local community and show other that making a contribution is easy and worthwhile.

this way slowly there will be more and more people who will pick up this attitude until a critical mass is reached at which point solving otherwise huge problems (like climate change) becomes easy because the majority will be supportive.

You can certainly join teams and projects that work on "important issues" - whichever you feel these are. You don't need to solve them all by yourself.

You also don't need to do any of the technical work yourself. You can do HR, funding, art, management for that team.

There's almost always more you can do.

1. Get your home in order, groom yourself, take care of your family.

2. Get more involved in your local community, church, charity, local politics

3. Get some issue awareness and vote without being a useful idiot

Those three categories are all things that most people are more than capable of and simply don't... "I don't have time..." meh, most people have time to spend an hour on social media, hours on youtube or playing games every day. There's plenty of time.

I was in the dating pool about 7 years ago, and one thing I always remembered was how much people would say they wanted a relationship, but wouldn't actually take the time to meet someone during the week after work. I mean, if it's something that matters to you, it's something you want in your life to accomplish you make the time.

You don't reap rewards and accomplishments without effort.

Great answer!