My courgettes and pumpkin got mildew on them and i couldn't help it but they still kept producing what they could and i had more than i used regardless. I could not keep my tomato plants from getting blown over, keep up with the cutting work, etc....but i still had an abundance of those.
In other words, if you have control over aspects of the work, it's more likely to make you happy. This seems to be consistent with the findings in the article.
As an aside to your last thought, there's a local teacher in my town that offers to paint home interiors in the summer time. He expects customers to do all the prep work and acquire the paint, but he will show up with brushes, rollers, etc. He does charge a fee, but it's much lower than any professional. When I asked why he does it, he simply answered that he loves painting and finds it relaxing, so he decided to do it on the side to help locals out. Maybe you could do something similar for yards in the neighborhood.
It was a royal slog that I dreaded in the beginning. But from the start it was a mood-improver, and subconsciously I caught on, because I've come to look forward to it and to enjoy it for itself. It gets me outside and in motion, with a reasonable amount of exertion. Doing it without hurting myself requires enough attention to pry me away from my other problems. It relaxes and somehow elevates rather than detaching me. The cleaning up satisfies my subclinical OCD in a deep way. Yard work has become a privilege that came with this property rather than a responsibility and chore.
So now the job is almost done and I'm looking longingly over the fence at my neighbors' wild yards. Maybe I'll make a deal with them, or maybe find some other way of generating happiness from being outdoors and working hard with natural randomness. Like gardening.