Not really sure if this concept is better. By setting a default, it automatically switches to Enable and lock icon appears next to toggle switch to signify that it is not available for any action.
This design is difficult to interpret, so the question is challenging to answer.
Here's my interpretation of the design:
- The user can selects a default. Only an item that is switched On can be a default.
- You want to prevent users from switching the current default to Off.
- If the user selects a default that is Off, the system forces it to switch On.
This third point leads me to a question. If a change in the default radio button can force a change to the corresponding switch from Off to ON), then what about the inverse? Perhaps a change to the switch's state (from On to Off) can force the default to a different radio button? If so, you don't need the lock icon.
Separate from this, please consider the comment I wrote under your question. The items in this list might be better in a slider, and the wording doesn't readily identify the items as a series of logical choices.
Finally, the word "Normal" is problematic. Microsoft Manual of Style for Technical Publications recommends against using this word because of its potential to offend. (What is normal? Whose default is normal? Is everyone else abnormal?)
From what I understand a user can activate a item indirectly by selecting it as default. While there is no technical reason to prevent this, I think the UI would become a lot easier to understand in terms of it causalities if items that are not enabled have their radio button for making them default disabled (greyed out).
You have one UI action here (clicking the default option on a disabled item) that essentially does two things at once (enable it, then set it as default), but from looking at the UI it's unclear if this is indeed the outcome of clicking it. The contradiction here is that a disabled item might also be unavailable for setting as default.
Why? When looking at this UI, it is unclear if a item that is not enabled can be a default. By showing a correlation between being enabled and allowing to set it as default, the user has a logical path of how to set something as default, even if it is not enabled in the first place. They first have to enabled it, the radio button for making it default will become active, and then they can set it as default.
As per my comment above, I don't understand the lock icon. If it is merely a duplicate information about this item being currently selected as default, you should remove it because it prompts the user to search for the meaning it signifies but isn't there.