[cantSpellSober]

Great question, this strikes me as very similar.

This appears to place more emphasis on static typing, and has less strange syntax (think of "shorthand" in Griffel).

The docs steer you away from atomic CSS, whereas Griffel's embraces them.

[naman34]

Griffel and StyleX arrived at very similar ideas and we've discussed the possibility of sharing more code between the two.

There are some meaningful differences in the API choices, but the high-level design is pretty much the same.