The architecture being open source or not has nothing to do with security. All high performance risc-v cpu designs are proprietary. The instruction set itself is open source, but beyond that you have as much visibility into the internals of the processor as you would with an Intel one. The only thing the license impacts is that you can legally make your own risc-v processor if you want, whereas tou can’t make your own x86 processor if you want (legally).
The architecture being open source or not has nothing to do with security. All high performance risc-v cpu designs are proprietary. The instruction set itself is open source, but beyond that you have as much visibility into the internals of the processor as you would with an Intel one. The only thing the license impacts is that you can legally make your own risc-v processor if you want, whereas tou can’t make your own x86 processor if you want (legally).