Individual solutions are mostly a fantasy. It's what we tell ourselves because the real solutions are fundamentally at odds with democracy and freedom. A few exceptions aside, people have never voted for a lower quality of life and personal degrowth. Instead, we prefer to slice and shift the blame around until no one is really responsible anymore. Your vision hangs on some sort of mass enlightenment that's just not going to happen. How many tragedies of the commons have been solved this way irl? Imagine being a fisherman in a Chinese trawler off the coast of West Africa. You could decide to stop overfishing. What then? You'll get fired and replaced by someone more desperate than you. The real world is a lot more complicated that "building a bird-friendly yard".

>All too often the "solutioning" defaults to the highest concentration of power, e.g. government/regulation – but that obviously isn't working at the speed it has to, and I suspect its because it's very easy to say "they should/we should" instead if "I will/we will".

That's the entire point of having concentration of power though. The decision makers can coordinate and manage things in ways the individual cannot. That alone gives them the responsibility to seek out a solution for worldwide issues. The lone individual is bound to follow basic instincts, rule of law and economic opportunities.