you've basically correctly answered your own question here:
generally a lot of it feels like A) she likes my physical appearance 2) immediate connection on a certain commonality/insight 3) luck
People spin their wheels and try new PUA methods etc, but I think in the end we all come to the same conclusion which is that if you are her type (and she decides within about half a second before you've finished your first word in the opener) then anything you say (game) is good enough
People used to memorise scripts and dhv stories and stuff for after the opener, because they would often 'run out of things to say'. But what you realise is that running out of things to say is basically a by-product of trying to game a girl who isn't attracted to you (in that situation, it's her job to MAKE you 'run out of things to say' lol). People learn all kinds of stuff in PUA books and don't realise that none of it would have helped them with THAT particular girl. When she is into, she's taking up so much of the slack and is elaborating on her answers and asking you stuff etc etc that 'running out of things to say' or whatever just isn't really an issue
Girls will make it very easy for you if you are her type in my experience.
And they will do all they can to make it impossible for you if you are not her type (so that you get the hint and leave her alone). It's not a 'sh1t test' in that situation. It's just an unwinable situation and you are just delaying the rejection if you try to 'game' her
But to put some meat on the bone, i've experimented with all kinds of 'systems' in game from mysterymethod to mode1 to RSD style and everything in between. I've basically come full circle. I can get laid with the most boring conversations. In fact, most of them are just like your described. the usual 'small talk' stuff, but when it's a girl who likes you, the conversations just tend to 'shoot off' into more advantageous conversations. It's not something you can force. You can of course try, and there's lots of techniques to do this, but they don't work if she's not into you. She'll shut them down. This is why you can watch the 'best' PUA's that we know of get rejected many times in a row (even if they go on to get laid with a girl every night). It's not something they like to talk about though! The whole 'why didn't your 'game' work on the first 12 girls??' lol. It's a game of numbers more than anything else. Not 'skill'
So yeah, worry about looking your best and increasing the volume and less about 'game' and conversation is my advice