Personally, I'm still using JSX/TSX to template my Web Components. (I'm not using React, I'm using the non-Virtual DOM approach with Butterfloat [1], but there are other small JSX template language options like Preact and snabbdom out there as well and also other non-Virtual DOM approaches.)

I like the type safety of TSX as well as the syntax highlighting. (As may be obvious with Butterfloat, I also prefer the power of RxJS over signals, but that's a longer conversation.)

[1] https://worldmaker.net/butterfloat/