You don't have to wait for the full fleet to cycle before you can use L2C or L5. L2C is already 15 years into its rollout and is widely available despite still being "pre-operational" due to it not having 100% coverage at all times.
You also missed discussing L1C, the 4th civilian signal being introduced with GPS III. This will work primarily with L5 to enhance indoor accuracy.
Should be pretty exciting when it becomes available. To the extent one can be excited about something that takes 20 years to be delivered.
[1] https://www.gps.gov/systems/gps/modernization/civilsignals/