China has 4 Tier 1 cities, 15 new Tier 1 cities and 30 Tier 2 cities, totalling 49 Chinese cities. The names of those cities is definitely going to be used up, since there are now 50 destroyers already in service + about to enter service with the PLAN.
Therefore, if the PLAN intends to operate 80-90-ish destroyers (which is what the USN is aiming to operate towards the late 2020s and 2030s), then the higher ups in the PLAN definitely have to eat into the list of Tier 3 Chinese cities (71 in total) to get more names for upcoming PLAN destroyers, which would grant China a grand total of 120 destroyers at any one time.
If there are concerns about eating into name allocations for PLAN frigates - According to Yichai Global, there are 338 cities in China. So with 120 being used for PLAN destroyers, that would leave 218 slots left for PLAN frigates, which I think is more than enough if the PLAN has no intention on stationing forces across the globe.