That's sad to hear, if true, and I'd have gladly paid for Tailwind if they'd had a "OK, so you use our CSS indirectly" program in place. I'm aware of "Tailwind Plus", but that seems to be React-only, and thus the opposite of where I want to be.
It's not React only. It has pure/regular HTML, React, and Vue. I have mainly only used the pure HTML personally as I use Phoenix/LiveView for most of my stuff, and it works phenomenally well and is very copy/paste friendly. The UI/console they provide is also top notch. For others who do use React, the React stuff also worked well too for one project I did that was a SPA. It's well worth the money IMHO.
"Our website templates are built using Next.js, so all of the markup is written using React"
And the individual components that make up these templates don't seem to have pricing attached, nor non-React usage examples?