If you continue to treat the battery pack as you do now, I'm not sure you need to worry. I have 32,000 miles on the pack and since 22,000 miles when I started to keep close track of the pack energy content, the usable capacity (based on driving at least 100 miles and using the car's efficiency data) has stayed between 29-31 kWh (there is variability in the data due to rounding errors). So, I've seen no obvious change in usable capacity for the last 12,000 miles, and if you look at my data, the curve has a slight positive slope. I typically go from ~25% to 90% per charge cycle and I DCFC when needed (about once or twice a month). Of course, my 2017 has the "big" pack and it is more than adequate for almost all of my driving.
2017 e-Golf LE, Multi Coat White with Black Vegan Leather interior