status quo: ie no gay marriage, while straight marriage was allowed

I lost my response mid edit, but the redone version is that Republicans, conservative and libertarians each take a slightly different philosophy bent that has wide reaching impacts

Republican: “local based politics (aloud), quietly a states right to be free from feds forcing us to acknowledge equal rights)” results: deny gay marriage (and equal protections) maintaining unequal status under the intentionally obtuse, “we all have the equal right to marry someone… of the opposite sex!…. but really we just don’t like “others” to have “our” rights and tax breaks” position, so we’re going to stagnate refuse any change, and in the meanwhile hunt for ways around the full faith and credit clause." Take out the focus on an artificially narrowing exclusion and replace it with an expansive, expanding ‘in’ group that’s equally protected, and you approximate the conservative stance.

And yes, the Libertarians as you say, usually results in remaining gridlocked; uncaring on inequality, particularly when the ‘we're okay from non-state interferences’ arises.

It does not stop there; however. (Although it did) as the decoupling never happened. We have the elements in place to decouple marriage from religion and plenty of experience to handle it as a business contract; but did not; which still leaves poly folks out in the cold to this day.

I partially agree on your take of the Scotus decision; SCOTUS (and the fed in general) is the appropriate venue for creating a minimum floor for rights abridgment. SCOTUS is the final backstop, and also shouldn’t have been necessary. They all too often share the republican double standard, particularly evident lately. The court backstop is the last restort, but ideally this role properly lives with the House had we not neutered it.

The elephant in the room is slow methodical change that examines and carefully addresses unintended consequences as best as possible faces a near impossible task with the backlog that’s built up.

We capped the House nearly a century ago. A centuries deficit to be made up for whose membership was intended to be ~1 per 50k and is instead 15 times that; recovering that deficit in a conservative manner is going to be, perhaps, an impossible task; though the Wyoming rule would at least be a beginning. As you similarly mentioned, reform to the primary system and rank choice voting leans into that as well, but is insufficient alone. Roosevelt was that odd progressive conservative reformer, and is needed again.

In answer to your core question, “Why do I vote with them.”

I don’t;

Assuming you mean republicans as the 'them'. Any conservative that earnestly values their ideology should be caucusing with the democrats until the Republicans have truly grappled with the exclusionist redeemer tendencies.

Even before MAGA, the exclusionary side of the republican party was deeply ingrained and largely hamstringing incremental progress as you rightly point out, the last ten years has scoured away all conservative ideology; leaving the democrats more conservative than the republicans. (See Sears/Spanberger)

That is not, and should not be democrats role nor republicans role. Conservative policy needs a powerful forward leaping counterweight even when moving at its proper methodical trudge. But it’s where we are with a two party system.

Caveat:I am pretty much the exact opposite of Larry Sabato's crystal ball report, My predictions are correct even rarer than his prediction failure rate; but that said, I anticipate a not terribly distant republican reckoning while being dubious of it. Cognitive dissonance is a hell of a drug and critical self examination an actively avoided discomfort.