Is there a cam switch available in which the key can be removed in all positions?
Yes, you can define a cam selector switch in which the key can be removed in all positions, but this will be a special product to be made (customized cam switch) by filling in the appropriate manufacturing grid (scheme sheet).
This sheet is attached to this documentation, in the bottom of this page.
To select removal of the key in a particular position, mark the required position with a cross.
Thus on the example of the manufacturing grid attached to this documentation (2nd page), if the key is to be removed in position 1, the sheet must be coded as follows: cross in column "x":