That’s odd, I’ve got a Pixel myself and Aurora just worked right out of the box on GrapheneOS. First time I’m hearing about Aptoide though, I’ll check it out.

Since you’ve already gotten some solid answers, I just want to point out that you can use Aurora to download and update apps from the PlayStore without the need for a Google account or PlayServices on your device.

https://f-droid.org/en/packages/com.aurora.store/