I want the strategic validation to my idea of creating ads for brand.(I will not promote)

I can create good Ai Ads and want to start working strategically on it, i approached 300 plus brands via email and nobody had a single good response, even when I'm giving 1 ad for free as i want to build my portfolio and want word of mouth plus some early reviews, but whole 300 brand not even one responded properly! Very disappointed. Can any one let me know how I get my services to people in a way where they least see it! Realistic amount people will pay, these are above avg to high grade work. How do I approach people and do lead generation! I want to know from you guys what you think! This is not an Ad please don't ban me.