I tried to describe the general attitude expressed by the 15 minute city advocates. Maybe I haven't tuned my wording right yet so let me be blunt. It's not about you. Stop personalizing it.

on zoning:
parking Requirements: defined by zoning regulations

legal structure: built to enforce existing zoning regulations

General Building code: 99% driven by safety and good engineering practice. Usually most of the building codes come from standard-setting organizations such as the National Fire Prevention Association. https://www.nfpa.org/Codes-and-Standards. Many municipalities accept these regulations as is because some have been sued for not following published building codes when something fails and somebody dies.

attitude of those with power: get into the power structure in the way they'll accept, get elected and then you have the power.

Need for teams of people: you underestimate the impact of very small number of people can have on regulation at the municipal level.

Angry horde: that will not change until you shift the Overton window on their perception in a nonconfrontational way. this is why I advocate for starting with rebuilding the urban core with high density living space. You can sell it to them much more easily because:

it doesn't threaten their environment,
it wouldn't increase car traffic,
it wouldn't significantly increase load on the city core,
increase the development of more entertainment offerings in the core.

for me, where the biggest wins would be getting rid of the crappy old slumlord housing. It breaks my heart to see kids with almost no exposure to nature living in housing surrounded by asphalt. That's another thing about bulk housing, the green spaces usually manicured patches of grass that you can't play on. This should be big patches of native plants and places where kids can get dirty on clean soil. Maybe even an embedded community garden. Most importantly, don't light the place up like it was Times Square.

In a nearby city, there was a significant disaster in trying to increase housing density. They chose to go the ADU route. Because it violated all of the rules I laid out above, there was a massive citizen uprising and rejection of this plan.

Your bigger barrier is going to be commercial groups. I've seen astronomy groups trying to get in place Light pollution control regulation at the state level. A single local lighting manufacturer has managed to spike that regulation every single time for the past 15 years. On the other hand, individuals have been successful at putting in light pollution control measures into local building codes.

Hear me clearly. Single individuals have made these changes happen. How? By getting to know the people in the planning board, being polite, nonconfrontational, presenting clear rational information and most importantly not being dogmatic rigid advocates. Individuals or small (2-3) Groups of individuals have been successful in changing conservation Board attitudes and regulations that accepted by the planning board.

I wrote what I did because of practical real-world examples. my experience is very different from what you have described so far. since your approach isn't working, would you consider a different approach?