sync for reddit crashed every time I opened it if play services are not installed (I am using an aosp android phone, grapheneos and lineages on a tablet) so it is kinda important that sync works without play services installed there is a better method for device attestation https://grapheneos.org/articles/attestation-compatibility-guide
Maybe lj could go down the swift backup route where purchases are tied to a Google sign in to avoid play services? You could buy the app from Google play via web, download it via aurora, then validate via in app login.
https://swiftapps.org/faq#whygoogle
Down side is lj would need a verification server (although he has servers for Reddit sync Imgur which he could repurpose for billing).
Disclaimer I am not a dev just a rando lemmy, Lemite? (Idk what to call a lemmy user)
I think the consens has been reached that Lemmy users are Lemmings. (Those cute furry rodents)
Watch out for them though, they’re pretty creative on escaping.