It helps to hire a new good coach. Firing the current coach doesn’t automatically make that happen.
To put it crudely, if Hue Jackson and Bill Belichick traded teams, keeping the EXACT same players, would the Patriots win the East and be in the running for the Super Bowl? Probably. Would the Browns be better than, say, 4-12? Probably not. Coaches are important, but they don’t work magic overnight. Turning things around may require a new system and a lot of new players who fit the system. That’s not a quick or easy process.