Direct answer
How do you do pSEO without creating spam content?
Healthy pSEO does not create thousands of pages by swapping only a city or one word. It creates a limited matrix of real intents, useful data, service, market and industry differences, internal links, FAQs and a clear action. Each page must answer a concrete question and add context a generic template could not solve. If there is no differentiated value, the route should not be published.