How do you gauge local market demand dynamics and market penetration?

I find this a challenging thing to diligence.

Determining local TAM and market share/penetration by a potential target or competitor is pretty important. Does anybody have any helpful frameworks, rubrics, or strategies for how to determine local market demand dynamics for a particular industry, service, or product?

I use Google maps and census data for population trends, but knowing how to use this data isn't always clear....Tools like Google trends and search console for keyword search volume might give some cues, but aren't hyper-local. Google also isn't the only method of discovery and doesn't represent the breadth of a local service industry.

When I hear that an owner has an abundance of leads that go un-serviced from a particular channel or multitude of channels, that's obviously awesome. Growing population is typically nice to see as well...

Does anyone have any good thoughts or strategies surrounding this topic?