I see this as an advantage rather than a disadvantage of RISC-V. By including only the most crucial and basic elements for every potential IC design, RISC-V allows a monolithic ISA model to be used for virtually every scenario. The goal of RISC-V has been changing since it was first implemented. It was never designed to be a performance leading ISA for CPUs like what ARM or Intel/AMD do because its original design goal was targeted towards industrial ICs.RISC-V is a mess because the available architecture isn't 100% adequate for doing a decently performing design. You need to add your own hardware instructions which make the processors incompatible with each other.
I think China is still better off with an ARM architectural license and making their own CPU designs.
Any specific implementations like CPU designs could be customized into that specific RISC-V design while still maintaining the full subset of basic features needed for cross compatibility requirements. This is the way China could organically infiltrate the IC domination of foreign firms as a trojan horse through the ecology this would gradually create. The incompatibility of a China designed and controlled customized RISC-V CPU is not really a disadvantage because the end goal is technology independence. RISC-V is just a way to use open source to begin this process but the end goal is full independence and if possible, technology control.