I'd use capture regex to get the first three numerals and capture the remaining string. If the remaining string exists, you can easily ignore the expected leading dash and your malformed semver suffixes will work and those can be trivially compared/sorted.
What about Go makes this different? That's how I'd solve this is any language
Agreed - especially when it is potentially unknown what might follow the first three numerals. Any performance hit would be mitigated by the corresponding reduction of the downstream logic.
What about Go makes this different? That's how I'd solve this is any language