When Airbus introduce their first passenger jet A300, they were being manufactured as below
1974 (first year) - 4 aircraft delivered
1975 - 8 aircraft
1976 - 13
1977 - 15
1978 - 15
1979 - 26
1980 - 39 aircraft delivered.
Europeans have passenger aircraft manufacuring experience since even before WW2, and started production of passenger jets in 1950s. So although Airbus as a new company in 1970s, they should already had a large pool of engineers and designers available, still their initial production rates were quite low.
COMAC's experience started in 2010-2020s and China's only experience was Y-10 which was based on Boeing 707, and the project was abandoned. So essentially COMAC started with near to zero experience on modern passenger jet manufacuring.
It is only to be expected of COMAC to delivered low number of aircraft in 2023 and a few years therafter. However, we might see COMAC delivered more aircraft per year than AIrbus (1978 15 aircraft) on the fifth year of operation. We will just have to wait and see.