So, at the end of Kieron Gillen's run, Kid Loki sacrifices himself because the Fear Crown is powered by his mind, and him ceasing to exist means Mephisto can't use it. But why didn't he simply ask Hela to send him back to ancient times alongside Leah? He would've stopped existing in the present day, and the Crown would have no power. Or, if the Crown was somehow able to get its power from a different time period, Kid Loki could've killed himself, arranged for someone to steal the Crown from Mephisto (Mephisto wouldn't probably have guarded it very well, since it would've become useless after Loki's death), then had someone resurrect him. In the Marvel universe there are plenty of ways one could use to bring a dead person back to life. Hell, the reason Kid Loki existed in the first place was because Thor resurrected Loki after his death. Why couldn't Kid Loki have explained the whole thing to Thor, and have Thor bring him back to life again once the Crown had been made useless? It seems Kid Loki accepted Old Loki's solution way too easily, especially considering that finding a clever way out of impossible situations was his forte.
Ikol was only ever in Loki's head. The real Loki was there watching and could step in at any time if Kid!Loki was using his time for something he didn't approve off.
Old Loki explains Kid Loki can't just kill himself, as a "dead you is still you."
Old Loki also states that there are other ways out, but Kid Loki doesn't have the time to find them.
Also, Kid Loki couldn't have just "explained the whole thing to Thor," as he couldn't reveal the truth, the condition of the three final conversations Old Loki granted Kid Loki.