But I am comfortable assuming that those reviews come from users that did install and use both apps. The opinions seems to be very positive for both.
I do find it interesting that Apollo had such a steep popularity increase in the last couple of weeks[1].
[1] https://www.similarweb.com/app/app-store/979274575/statistic...
So, the large amount of positive reviews for the mobile clients also speak positively for the platform. Is that what you are theorizing?
I think it's less likely to happen with Apollo if at all, because those users are clearly aware of, and even have front of mind in the moment, the distinction between Reddit the platform and Apollo the client. The number of people who discovered Reddit via Apollo must surely be extremely small?
Lots of people probably install the official app, just to try it out, but that doesn't mean they actually use it.
I installed it myself a long time ago, but I never use it because it's garbage compared to Boost (my preferred 3rd party app).