I think the technology used in LTE-NR DC UL power is dynamic power sharing technology or without dynamic power sharing.
Dynamic power sharing means that the UE can operate with P_LTE + P_NR > P_powerclass configuration .
UE supports simultaneous LTE and NR transmission in LTE – NR DC for dynamic power sharing.
when UE is configured for NR, P_LTE can be configured up to P_cmax and P_NR can be configured up to P_cmax.
P_LTE + P_NR > P_cmax or P_LTE + P_NR = P_cmax
when the sum of the configured P_LTE and P_NR is equal or less than P_powerclass. If the sum of the configured P_LTE and P_NR is more than P_powerclass, the UE can only operate with TDM based single UL transmission.
To ensure UE simultaneous UL transmission for LTE and NR during LTE – NR DC the network needs to configure P_LTE + P_NR ≤ P_powerclass for the UEs without dynamic power sharing capability.
Note:Above info is taken from some research papers not from 3GPP docs.