I remember when both S/X had their "refresh-refresh" around Feb/Mar, and S got matrix lights but X didn't... multiple Tesla service advisors were *convinced* that the X had matrix lights as well. More than one told me "these latest refresh models are simply BLINDING".Wierd. To me my Plaid Model X lights (del'd late 5.15) are 3x as good and as bright as my old 2018 Model X. And Plaid X does not yet have matrix.
Couple this with multiple reports from pre + post refresh owners (like yourself) claiming that the latest refresh Xs have significantly brighter lights, and I'm thinking that the X headlights did in fact get an upgrade... albeit just not to "matrix" lights.
Some have speculated that Tesla's current hardware implementation for matrix lights still cannot satisfy the NHSTA requirements to enable the matrix functionality. They may be enough for Europe (and elsewhere), but could very possibly never get enabled in the US (until newer models are shipped). So if that holds true, it seems possible that the X won't get Matrix lights for a long time (perhaps years) if the latest lights are bright enough.