For updates to the schema then some sort of migration system surely exists for your framework of choice. The frameworks I’m familiar with (Rails, Laravel and .NET) all have migrations and schemas in code.

For one-off changes to existing data what has served me well so far is implementing an audit log from the start coupled with making sure that records are fudgeable by a select few admins.

This means that a few people can make changes to nearly everything from the interface rather than having to log into the DB directly. At the same time there is a record of changes done and the ability to comment on and revert them.