When you can get her attention she seems to enjoy playing a lot of different things, say for example she enjoys sitting with me playing her mini park, with my guidance and prompts
To what extent does she relate to the emotional states of others? It could be that she enjoys making you happy by playing with you, and when you quit the game she wanders off just the same as you wouldn't stay at a swing park for your own enjoyment after a child has got tired of it.
Perhaps what looks like enjoying the game is more that she's enjoying interacting with an important person in a way that makes that important person smile? And stay! If you've already left, there's no need to carry on doing that thing that makes you stay, so why not go back to tapping on all the glasses in the house to see what noise they make, and other things that NT children don't usually play.
She may, of course, truly be enjoying the games you play, she may be more interested in whether or not you are engaged with it. Girls on the spectrum are great ones for doing whatever makes a dominant personality happy, because that looks just like friendship.
Have you tried giving her play ideas, and also rather than just either staying or going, an intermediate step where you pop out of the room really briefly. So maybe you play with the Lego bricks (or whatever) and if she shows an idea you could say "wow, yes, we could stack them", copy her for a bit, nip to the loo, come back, either congratulate her great progress in your absence or if she's not continued try "Now, where was I, I was stacking my bricks". If she's onto something else with the bricks, tell her you're going to do that next when you're finished stacking, if she's away, tell her you're out of ideas how to play with the bricks now, can she help you. If she won't come back to them, leave it.
My DD loves lists and instruction cards. We'll sit together and make a list of ways you can play with a given toy or play set. We leave the list with the toys to remind her as she genuinely just forgets! Without a reference or another child to encourage her, she'll just fall back putting dolls in a line, then two lines, three lines, back in one line again... Helps that she's old enough to read, though.
What about other children, how does she do with company? A NT child might be able to guide her in the ways of play in a way that's much more natural than how adults imagine children should play. Other people's children are free to borrow!