I also did some experiments in this space as I have the same complaints about Tailwind

https://github.com/aziis98/preact-css-extract

I made this as I couldn't stand writing another 2K lines css file and wanted to try the atomic css wagon without having to switch from preact or having to learn tailwind

Happy to see a new CSS-in-JS lib. All of this madness about runtime performance costs does not apply to 99.9% of the population. But good abstractions do. And then there's latency, and machines are getting faster, and browsers getting better, etc etc. This whole argument and the related FUD was all a non-issue to begin with, at the great cost to DX.