I’m currently running my first published campaign. (pathfinder 2e) and unlike when I tried to do everything myself I’m able to keep it up when life gets busy. Losing momentum had been my biggest campaign killer. Besides the story having fun & challenging encounters ready is a huge time safer. Making my own shit is still fun but much more enjoyable when not in a vacuum, using the pre-write as a frame to build on as it were. Also campaigns can be reused repurposed and recycled.

If you do run a pre write make sure your players don’t come in expecting a sandbox.

There are ttrpg systems that work great for improv heavy style of play. Blades in the dark as example is focused around a city. The book gives you a ton of active factions in the setting, their goals, methods/means/style, friends and foes, level of influence, locations and some members of note.