Every company starts out privately owned. Being publically owned means you are legally required to put shareholders' interests first and thus essentially be purely profit and growth driven, leanding to an unsustainable cycle of infinite growth which is a major cause of the enshitification of everything as we know it today.

Private companies can at least set their own goals and do things other than chase profit. Typically, that's either "chase profit so the owners can cash out" or "focus on providing an actually good service/product so that profit/growth will follow".

Private Equity is probably what you're thinking about, where a PE firm purchases a company that's either already private or they make it private again. There are many PE firms with many different management styles and goals, but the overwhelming majority have a goal of squeezing every last penny out of a company using any means necessary and fucking over the employees as much as possible before divesting it and moving to the next one.