Sorry to hear that but if you already tried and retried all these steps then it's hard for me to tell what the problem is from afar. Maybe you can use another device to play? The Play Store never offers adult games afaik, you always have to get them through unofficial means.
Viewing post in Step by Step: Installing Eternum on Android comments
I just have 1 device, hey the eternum it's like a same from once in a lifetime I actually play it right now but why the eternum I can't play and the download link is broken is it because I'm using Android 14 the device problem I actually have problem to download the once in a lifetime game when I download the game halfway progress it stop and say forbidden but I manage to see the support download link and I download the once in a lifetime game through that way it's GDrive download link it work, but eternum don't have that if this cause by the device fvk this device yeah
Is it possible they fix the problem in next update, I see some murmur in comments we have the same problem I'm willing to wait until next update I gotta pray they fix the problem so that others may can play like me to experience the beautiful of game....
I'm willing to wait the next update I just hope they can fix the game... Btw the once in a lifetime is peak yeah it was good game