I do contract work for a company that has it's pretty customer facing site as a mix of angular/react/react native and .net core apis and the less pretty interna

I do contract work for a company that has it's pretty customer facing site as a mix of angular/react/react native and .net core apis and the less pretty internal staff site which is vanilla html, js and c++ cgi apis, so I get to work in both on the same day. The internal c++ site has been running for ~25 years. The customer site seems to need to be re-written every time we add a new feature, because all the tech is out of support and there are breaking changes to libraries