Goku was obliterated in the world of void. When that happens, he wasn't sent to U7 King Yemma or any other judge of the otherworld (I am hoping the other unis judges are like Hel, Anubis, Hades etc) but rather met the Ultimate god of creation, Zalamas.
Zalamas, banished by Zeno into the Realm of the Erased, but still managing to see some of the show--along with rest of those erased--is surprised to see Goku in person.
"Lord Zalamas," Gowasu says excited, "this is the warrior Goku from Universe 7!"
Zalamas makes no comment. She's a short figure, that looks like that toy silhouette.
"Perhaps we can convince him to wish us--all of us back--with the Super Dragon Balls!" Rumsshi says excitedly.
Goku stares back, "Oi, Gowasu, where am I? What happened?"
"You blew your load and it sent you here," Basil growled. Roth and Sidra were glaring from behind. "Looks like you're stuck here with us for the rest of--"
"I AM THE GREAT ZALAMAS" the god shouts "STATE YOUR WISH MORTAL AND IT SHALL BE GRANTED"
"Oh! Uh...Can I get back to my fight with Jiren?"
"YOU SHOULD CONSIDER AMENDING THAT WISH"
"Perhaps you should wish for the power to defeat Jiren," Gowasu whispers to Goku.
"So you can wish us back," Rumsshi adds.
"Ugh," Goku frowns, "But getting a cheap power up like that feels like cheating."
"DON'T WORRY. YOU WON'T BE RECEIVING A FREE POWER UP!"
Goku spends what feels like three years training with all the erased GoDs, Kais, the greatest warriors of 9,10 and 13-16 and Zalama. He befriends them, learning and sympathizing with the misery that is not existing--a perpetual limbo of nothingness and eternity. A similar feeling to reading my post.
When Goku has finally managed to crack the Ultra Instinct Omen technique, Zalamas has gathered enough energy to send him back to the arena.
"Geez, I'm so excited to try out this technique against--"
"GO FORTH AND WIN THE TOURNAMENT, PUPIL. AND AS YOU RETURN TO EXISTENCE, DO NOT FORGET YOUR PROMISE TO ME"
"Of course not, Zalama-cha--"
"DO NOT CALL ME THAT. I AM THE GREAT ZALAMAS. MAKE SURE YOU TELL THOSE CURSED ANGELS AND THAT DAMNED ZENO--"
"Okay, goodbye now!" Goku disappears through the portal, UI form activated.
"...THAT YOU LEARNED THIS TECHNIQUE FROM THE GREAT ZALAMAS AND INTEND TO REVIVE THE ERASED UNIVERSES AND ME."
"What was that, Kakarot?" Vegeta asks, miffed. Goku, trying to recover from that last punch from Jiren, is having a hard time remembering how to even talk. The past three years in eternity were gone, along with memories of his first 3 years of life, the name of his brother, the name of his best friend ___...
"I'm not quite sure myself," the Saiyan grins, body throbbing.
The Grand Priest shrugs when he hears the collective screams of a trillion and one broken hearts.