The theme has very little to do with the SEO. You’ll just need the ability to check technical SEO with the correct placement of content tags, h1, h2, p etc then use the media library for all your image alt tags and optimising them for small file size and quality.
You can then add all in one seo, yoast or other tools to manage your page meta.
Find a responsive theme you feel works best for the audience, brand, objectives you’re after.
Could also look at WP builders with Divi, Elementor, Beaver or Oxygen to design and build something more custom if you want quick and easy.