If there was a way of tricking the app to think it is always online, the real status could be obfuscated. WhatsApp probably uses some Android and iOS API to kno

If there was a way of tricking the app to think it is always online, the real status could be obfuscated. WhatsApp probably uses some Android and iOS API to know when it's open, tapping into that could confuse the app and make the online status pretty useless. LineageOS (previously CyanogenMod) had a Privacy Blocker or something like that, which you could block specific apps access to major APIs like Media Access, Phone ID Access, etc. It's been a while since I last used that, don't know if it still exists, but it sure helped my paranoia. It was fun seeing apps trying to access all sorts of stuff on my phone just to see them being denied access. Nice Death Grips reference btw.