It's not possible to save 'No strategy selected' in the Base config under the 'Strategy' tab of your trading bot. After saving 'No strategy', the 'Signals only' button will be enabled again. This is hard-coded and cannot be changed.

If you don't use any trading strategy or trading signals, nothing will happen to your open positions when 'Signals only' is enabled.

If you save 'No strategy selected' as shown below:

Then it will look like this after saving: