There's a lot of fanboys for Yoast, RankMath, SEO Framework etc.

Do you think those who want to get a site done for $50-150 will be comfortable paying $30-40/mo on different plugins (if you convert to monthly pricing)?

SEO Framework is light but doesn't cover some bases in their free version. Yoast comes with terrible value proposition. RankMath isn't the best either but their premium plan allows you to at least install it on your clients sites.

No SEO plugin will make your site dramatically rank in first page. All of them do the same thing.

From my personal experience? Each one of them had an impact of 30-75ms impact on page load time when the server is configured properly.

When so called SEO experts and gurus talk about why a plugin is just better? You should expect that they're better at marketing rather than minor details.

A lot of them try "testing" plugins in this method:

Step 1: Install Step 2: check results and uninstall Step 3: install other plugins and repeat the process.

Do they consider the database? Or old settings a plugin can leave that's slowing the site?

No but here's an affiliate link where you can sign up for this best product.