I like how this flashback is interwoven with the present narrative, at least for the time being. Normally I would expect Oda to make a crude cut at a cliffhanger for a loredump. And this flashback is actually packed with feeling, unlike the overhyped babble chapter when Garling first appeared. And the story of God Valley and Rocks just have become even more intriguing. Saturn and his powers are pretty interesting and impressive. But young Garling looks like a normal chinless narcissist with too much hairgel, not really good-looking, e.g. compared to Shanks. One shouldn’t really go by murder-hungry CD simps.
For what happens next, the Iron Giant appearing seems like a very obvious solution. And I guess Kuma is an option, as was mentioned.
Something more far-fetched I could imagine is Zoro and Lucci suddenly bursting through and knocking the hand down (accidentally).
I also wonder if Zoro’s brush with Death in Wano (and King of Hell title) will come in handy against whatever power Saturn or the Gorosei wield (sooner rather than later).
The Grand Fleet will likely appear, although this won't save them at the moment. (Plus maybe Dragon or BB, although this is also unlikely to save them at the moment.)
Another thought I had is if maybe Vegapunk is able to publish the incident (regardless of its outcome) and if this has something to do with the "Egghead Incident".