In all likelihood, it would have taken the erasure of the entire Marvel multiverse/omniverse(ie. infinite universes) to defeat him without a plot device -- and wiping out infinite universes is obviously FAR beyond any output we can logically infer for Zen-Oh.
*I'd also add that even 238 MJJ is a universal reality warper, so he can still beat Zen-Oh if he acts first. That said, both Jaspers' are dipshits(hence the "mad" title), so it's hard for me to imagine 238 being smart enough to full-on attack Zen-Oh before he was erased. 616 would stuff the entire DB franchise into a soda can and put it on his mantle with a gesture, though. /shrug
Remember MJJ is a British Politician, he will probably, cause himself to go into recession as he brexits from reality leaving the multiverse in turmoil and its citizens screwed.
Demon God Demigra after absorbing Toki-Toki, a bird that literally births timelines out of eggs, states and is stated to be capable of destroying all of infinite history and rewriting it in his image. In this context, all of infinite history is infinite timelines, and hell, it even includes “the real world.”
It is also repeatedly stated that Demigra transcends time, he can seamlessly transition throughout different timelines, and is thus imprisoned within the “Crack of Time,” a plane of existence entirely separated from time itself.
There is more to it, but basically Demigra is a legit reality warper who can erase all of history (infinite timelines) at his peak in Xenoverse 1. However, pre-RoF/post-BoG Goku and the protagonist are able to defeat this Demigra. Later on, Demigra unlocks a new form and becomes even more powerful, but Goku has grown so much stronger that even in Base he can defeat Demigra, and for sure with SSJ1. IIRC, even this takes place before the Tournament of Power in Heroes/Xenoverse continuity.
When we have Base Goku operating at that level, yet SSJB KK Vegetto is getting bodied by Base Cumber, I can see Xenoverse being able to overcome MJJ when we introduce MUI, Fu, (who can also erase infinite timelines, and may be even stronger than Cumber), Cumber, the angels and gods of Destruction, GP, Zen-Oh, etc.
__________________ ”You presume limits to my power. There are none.”