As your business partner is not capable of editing the site code, the easiest way to go in a case like this is to use a CMS like WordPress. You need a system that is easy to update and maintain. WordPress is meant for this and a good choice but the options don't stop there. There's Webflow, Studio, Squarespace and bunch of others. But as you said, you would be using the blog platform to get leads and WordPress is pretty much meant for blogging so it's obviously a great choice. It has a bad rep and "real" web developers don't like it but the thing is.. It gets the job done.
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If you have time and the possibility to build an epic site and you feel that it suits your needs, then go for it. Look for things like Gridsome and GatsbyJS (Vue and React based, you would need to study a bunch of new stuff) and maybe a headless CMS (like Prismic) so the site would still be easy to update for a person like your business partner who could create those new blog posts fairly easily.
Not a site but a builder: https://studio.design is hands down the fastest website builder I've ever used. I know html/CSS and a little JS, but with this, I've not needed to use it while making all sorts of layouts.
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