Nobody knows how to play against her or with her. Not even Ascendant/low Immo. I play her lots recently cuz I get Pearl once per two games. I've gotta say, if anyone plays Astra on that map, just play connector or mid link. Don't make the mistake of playing A. At the start I used to anchor A, but it's so bad. You can just setup a smoke and a gravity well if the enemies do an A rush. Setting up a smoke on mid link and Art too. They will barely ever push through mid doors if it's smoked. And if they do, just call in your teammate to peek out from B and fight them with a suck or something. B hold is the only problem if you don't have a Viper on the team. Just play retake on B, it's impossible to hold even with all the Astra util. You can just ult or smoke off pillar when it comes to retaking the B site.
I hope I'm not wrong with most of this stuff. If anyone has a better way of playing Astra in ranked feel free to say. But personally this is my way of playing Astra on defense. Hope I helped somehow!