You can’t just find some idea and do things. There are road maps and promises made to manager and product.
What incentivises your manager to just agree to let you work on your own projects?
* You have someone whose job or as part of their job is to it is to discover these kinds of internal organizational efficiencies and automate them. Something that organically comes up like this gets assigned to that person.
* Managers are not incentivized to stick to a rigid schedule or metrics based on an inflexible roadmap.
* Flexibility and autonomy is built into developers' schedules so they can work on things outside of just their rank-ordered task list.
There are strict timelines that span months if not years, often optimised to a large extent. There is little room for spontaneity and organic projects to come up.
(Although, there is also the company that claims to encourage it, and then buries you in bureaucracy...)
What incentivizes you to ask permission?