+2
There was a problem with early Star Trek. They would visit these strange new worlds acquire mind-bending technologies and then promptly forget about them next week. They meet aliens who adjust the engines so the Enterprise can travel at warp Jesus to travel to another galaxy in a human lifetime. They never use it again. McCoy synthesizes a potion in sickbay to accelerate humans to superspeed. They never use it again. McCoy then figures out how make psychic powers in a chemical brew. They never use it again. Within an espisode, it's fine. Over the course of episodes, it's silly.
A multiverse can work, but it should be a highly limited. Our world eraser should be like a genie granting a single wish rather than endless worlds granting endless wishes. It should be hard to access the world eraser. It should be costly to use it. It should be limited in terms of use as matter of in-world jibber-jab. It should be just barely accomplished by the hero or villain. It should seem unlikely to the audience that our characters will be able to pull it off again. If nothing pushes back against the infinite there are no stakes, so you need limits. You need Kryptonite. You need those eagle to be unable or unwilling to fly you to Mordor. You need the Talosians to keep their illusion technology to themselves, because they realize human would kill themselves with that much power. Bind the infinite as you will, but bound it must be or your story will have no stakes.