I have a lot of similar thoughts myself. Justice Gorsuch brought reason back to what has been an incredibly unreasonable debate and did so in a way that protects individual rights for all and doesn't play any word games, especially not any with sex vs. gender.

Justice Alito's dissent, which Justice Thomas joined, is nothing but word-think; he literally does almost nothing but quote dictionary definitions of words. I read the main part of his opinion and just skipped over the rest because I found his argumentation to be entirely unsound.

Justice Kavanaugh's dissent is far better, but his only real argument seems to be his general disdain for retroactively applying existing laws to cases their authors supposedly hadn't considered. I especially didn't care for his argument that it was a bad thing that Gorsuch's opinion means the original law back in 1964 should have applied in this case this entire time. Yes, it should have applied. That's the whole point. People generally got less bigoted in the intervening 56 years and therefore are more willing to accept a textual reading of it coupled with reasoning.

I'm sure there were plenty of people even back in 1964 who absolutely thought one day this law would be interpreted to include homosexuals, they just didn't publicly say it back then. Kavanaugh's argument only works if none of the people who worked on the law imagined at the time that one day it might apply this way. He tries to argue with examples of some people then who vocally believed it shouldn't apply to homosexuals. That indicates to me the topic was discussed and in the end a decision was made to not include any specific language that would prevent it from being interpreted that way nor any language that would force it to be interpreted this way.

In other words, I find Kavanaugh's evidence to be not in support of his opinion, but in support of Gorsuch's opinion. I still respect Kavanaugh's opinion, I just find his argumentation lacking.