Anyone actually measuring seo roi successfully?

Mostly, yes, as long as you accept it's an estimate. Set up your leads or sales as key events in GA4, then look at them filtered to organic search, by landing page. If you sell leads rather than products, give each lead a value: average deal size times your close rate. That number against what you spend on content, tools and whoever does the work gives you a rough ROI. Two caveats. Split branded and non-branded queries, because people searching your name would probably have found you anyway. And last-click attribution undercounts SEO, since a lot of people read a blog post, leave, and come back later through a direct visit or an ad.