I have lived in two different US cities that planted native fruit trees in the public spaces. Apples, pears, serviceberries, pawpaw fruit, etc. People were encouraged to enjoy. That isn’t what you call a food forest, but it’s a “do-able” thing that cities could undertake that would help the local pollinators and residents.

I have been working toward a permaculture garden and landscaping with native species. Mostly consisting of small slow changes to increase insect habitats and food sources for local fauna. A local nature conservation program nearby sells permaculture plant sets to encourage the use of non-invasive species. I think the idea is gaining awareness. You might enjoy the documentary biggest little farm.

https://www.biggestlittlefarmmovie.com/

I purchased and studied this two volume set because it is what was recommended by a local university.

That was a little over ten years ago when my family first moved to Maine. We have a five acre property that we wanted to turn into a food forest. The first plantings we made were trees. Namely, black walnut, several species of apple, weeping willow, pear, etc.

Once these reach a little more maturity, I’ll plant the understory. Things grow slowly here in Maine, but we will eventually have a huge food forest.