There are several FOSS clients already in F-Droid. I'm trying out Jerboa, Thunder, and Liftoff. Lemmur is also on F-Droid but it's abandoned and doesn't seem to work well.
Yes, I was an Infinity user myself, great app.
Now I have "Stealth for Reddit", which is a Privacy Focus Client for reddit, still work because it uses an experimental feature to get information from "old.reddit".
Boost was not open source, I think it ask for that because of the 1 time payment for removal of ads.
Edit: I think jerboa at the moment gives me almost the same itch boost have, If only it can open link through its internal browser it would be the perfect app for me. Liftoff had this but seem to crash for me every time when I'm logged in which is unfortunate.
I had a another look, when clicking the details there it looks like it is taking purchase history for the financial information. It mentions about analytics purposes. I guess its just for keeping tabs the number of purchase for the app. That makes me think perhaps at some point the app (boost for reddit) was designed to track a subscription like system but nesr the end they just decided to just go with one time purchase, and it got a carried over with this new app. Then again I'm not familiar that much with app development if it really need that permission to keep tabs for purchases.
Thanks for turning attention to those. I got curious and looked at the ones for Boost for reddit and they seem about the same. A bit funny to see that the settings for the app only show Notifications as a granted permission (and no other possible ones). Can anyone familiar with Android app development chime in with some details?
I'm pretty sure it only says your data cannot be deleted because lemmy is decentralized. Meaning anything you post is not in the hands of one entity like Reddit was. So you can't just request to delete you information, because it exists on multiple instances that are in the hands of multiple people. I don't think this has anything to do with the developer of Boost.
If you click on the See Details button those will make more sense. It seems to be all for an ad supported version like Boost was for Reddit. So purchasing the app should stop using these permissions.