I think it may be different in some phones, but on mine I just long-press the icon and get a menu where I choose app info. From there I click 'storage usage' and click 'clear data'.
Jerboa sucked for me since I downloaded it. Constant logouts, unable to login after entering my creds, not showing my account until I closed and reopened the app, not letting me see my comments or saved posts, and constantly getting a "log in first" error when I tried to save a post. I ditched it and downloaded Connect, and thus far it seems to be the store-brand version of Sync, my absolute favorite Reddit app ever. When the dev releases Sync for Lemmy I will switch to that, but until then Connect is usable and pleasant.
IDK why, but this kind of interaction was somewhat rare on Reddit but it's everywhere here. It's like everyone is giving each other the benefit of the doubt or something. I hope it stays like this and doesn't get enshittified.