Some managers like to assign projects to people. It makes it easier to understand who does what, and whom you should see

but when they don't have new requests for you, they won't always create them out of thin air (they are busy, and you know the app better than them anyway)

Propose ! You can use your knowledge of these projects to refactor code, or improve them ! Improve the code ! Improve CI/CD !

You can also have a conversation with your manager, to ask him for what will come next.

Also, don't worry about some large companies. They have solid finances, and HR don't care if some employees spend a few weeks, sometimes months, without a lot of work. They will assign them to new tasks as needed.