Four rotating frames cover the year: real work (before/after, on-the-job. Your strongest content), useful answers (every customer question is a post; your intake calls are an idea machine), proof (reviews, milestones), and humans (crew, community, behind-scenes). Nobody follows a logo for promotions.
Idea supply is a capture habit, not a creativity problem: every job photographed, every question logged, every review screenshotted = thirty posts a month collected in passing. The businesses that 'never know what to post' are the ones not writing down Tuesday.
Cross-posting the same content everywhere: mostly yes. Reformat (vertical for Reels, plainer for Facebook, professional frame for LinkedIn) rather than reinvent. One good job story is a photo post, a Reel, and an email; repurposing is the whole game at owner scale.