Multiple pages. Always more content. More more more. The better you focus it and move your page authority around your site the better.
Define main service keywords, build main landing pages for those and add content content content that backs those up. Real, good quality content. Testimonials that lead with service area and offering introductions. Blog posts of completed projects that highlight keywords and locations.
But most of all, way more important than this on many levels, make sure your website loads as fast af on every device you can test it on