In general, you should only fully charge your electric car when you need the full range. Also, it makes sense to set your car to be fully charged just before you start driving. Most of the time you can program the charge or choose the charge current yourself so that the car is ready with 100% charge just before you start driving.
Is the SoH shown on the vehicle display correct? Answering this question is not as easy as it seems. The relevant SoH of a battery strongly depends on the reliability of the data used for SoH calculation.