I believe you can do it from the Aurora Store under Manual Download. But you would have to have bought the app already as you would have to do it having signed on using your own account on it. Since you cannot purchase it via Aurora. I have done this for some icon packs and a few other aoos that already purchased.
Be aware, as I mentioned elsewhere, even if you download it, if the app constantly checks if you bought the app via the Playstore then unless you have the Playstore running and signed on as well, then it will likely fail to load/launch and will tell you that you have not paid for it. Even if you actually have, as it cannot verify it without the PS.
There are someapps that I have purchased, and that I can download but they will not work after they are installed.
Yes and no. It is more if they are intended to call home once installed. I have backed up some apps and installed them on a second phone without issues. It does depend if they call home via the PlayStore. I can tell because I do not have the Playstore installed on my phone. Some apps will try to reach the Playstore Pay(?) API to confirm if you have bought it. So even if you did before, it will check, anyways. Like, Tasker will constantly check, while some games or icon packs may not. Specially the ones that are one time payment purchases or have a separate APK like Hermit.
Have not used it in a while but there is a fork of Infinity that works on Lemmy, already.
I would sort of argue your point, but sadly… I have to side with you, if we are talking in the aggregate. You are 100% right. Most people do not follow best practices and will do things without knowing of the possible negative consequences.
Good points.