It's a bit confusing, but there's both "ROCm" and "ROCm on Radeon" releases. Despite what seems to be implied by the names, the standard "ROCm" releases support both Radeon and Instinct GPUs. "ROCm on Radeon" seems to be ROCm as packaged and released by the team that does "Radeon Software for Linux" instead of by the original ROCm packaging and release teams.