Is timebomb symbolic rather than real ?
Obviously, this theory probably won't be popular and I would not be surprised if I'm probably downvoted to the shadow realm, hell there is an entire subreddit dedicated to outright opposition to this idea (idrc the art is cool and people are devoted don't have an issue with it though some of the NSFW is questionable) but I will go through with it anyway.
In my opinion, I think its very possible if not even likely that the purpose of the AU was NOT to set up an Ekko/Powder love story, it served more as a storytelling device to show that there was still good in Jinx and she is only like this due (mainly) to circumstances rather than her being an evil person (though I find it unlikely he will forgive her for killing his friends). The fact of the matter did Ekko love Powder? Probably, it does explain his actions during the S1 fight. He has accepted that Powder is gone in his world but his perception of Jinx has changed radically
To him, Powder and Jinx are different people but he comes to accept that Jinx is not a lost cause and is still worth trying to save. As for Jinx, this is a complete wildcard that is impossible to know does she actually love Ekko? I have no idea but even if she did I think it might not matter considering where she is mentally before the final battle, the lowest point in her life. It just happened that Ekko was the only one who could convince her to not kill herself like Ekko was the only one who could convince AU Powder to bring out her creativity again. Perhaps they have become at least somewhat friends and believe that saving the world is a matter of working together and that Ekko telling Jinx of AU powder is a way of giving Jinx hope that she can do good in this world. Just my two cents feel free to either give a concrete criticism, open discussion, or hopefully not tear me apart.
concrete