Make values set in the inspector at runtime become the default

Am finding myself often editing parameters in the inspector at runtime to find the actual values I need.

For example stuff like player speed which you cannot meaningfully decide just from the scene view.
Then currently I have to literally type them out into a file or on paper and after stopping the game, write them back into each field.
Sometimes I also forget what I have changed and it is very frustrating.

Is there no easier way?

What I imagine as a solution is just some small buttons next to each value (or one per line, for example like in those locations): 159423-capture.png
If clicked, it should make the value of this field persist and become the default when the game is stopped (just as if typed with the game off).
This shall work independently of prefabs etc.

Could the editor be adapted to support this as a plugin, or does someone know an asset for this?
Cannot really imagine that I am the first one needing such a solution.

Huge thanks in advance!

Well ScriptableObjects are commonly used for configuration data like that.