Hi Experts.
How many max carriers can be aggregated in ENDC?
Admin note: this post was updated with image below.
In 5G NR Phase-1, upto 16 CCs (both contiguous and non-contiguous) can be aggregated.
Source: 5G NR Carrier Aggregation (CA) basics | Carrier Aggregation frequency bands.
4G LTE-Advanced Pro supports up to 5 component carriers (CC) as shown in Figure 1. 5G NR CA now supports up to 16 contiguous and non-contiguous CCs and can aggregate new 5G bands up to approximately 1 GHz of spectrum. Dual connectivity allows a user equipment to simultaneously transmit and receive data on multiple CCs from cwo cell groups (i.e. a master eNB and secondary eNB). Using EUTRA + NR – dual connectivity (EN-DC) allows networks to take advantage of 4G and 5G spectrum to increase user throughput, provide mobile signal robustness and support load-balancing among eNBs
Source: 
Also there is important topic is ATBC.
CC support is depend on ATBC according to the 3gPP 2013 release.
Class A: ATBC ≤ 100, maximum number of CC = 1
Class B: ATBC ≤ 100, maximum number of CC = 2
Class C: 100 < ATBC ≤ 200, maximum number of CC = 2
In a practical way, maximum 5 in NSA.