For server workloads there can still be plenty of non-trivial architecture-specific dependencies besides the core OS itself, such as the JVM and other JIT-based interpreters.
Python 'pip' packages, which often have native code dependencies, may also lack official RISC-V builds.
You should be able to use QEMU user-level emulation to run binaries from other architectures on a RISC-V system, while using native code for the rest. Alternately if the code is available and reasonably clean, you could try a RISC-V build yourself. (Obviously not for the JVM and other JIT-dependent stuff - though these ports are ongoing too - but for most smaller projects it should work fine.)
Python 'pip' packages, which often have native code dependencies, may also lack official RISC-V builds.