Most FLOSS stuff will compile without issue. Practically all the portability issues got sorted out when x86_64 became a thing, stuff gets regularly build for arm32 and arm64, and basically all inline assembly has alternative generic code paths which actually won’t be that bad because it’s way easier for compilers to output good vector code than it is to output good SIMD code, less room for hand-optimisation.
Once the kernel and drivers are up and running you’re good to go because the vast, vast, vast majority of code doesn’t care a bit about what CPU it is running on.
Most FLOSS stuff will compile without issue. Practically all the portability issues got sorted out when x86_64 became a thing, stuff gets regularly build for arm32 and arm64, and basically all inline assembly has alternative generic code paths which actually won’t be that bad because it’s way easier for compilers to output good vector code than it is to output good SIMD code, less room for hand-optimisation.
Once the kernel and drivers are up and running you’re good to go because the vast, vast, vast majority of code doesn’t care a bit about what CPU it is running on.