i work with c#
that repo is good to get an internship but its not really impressive. its all crud and parsing json, still, maybe they're enough to impress a recruiter for an internship as development is not as competitive in brazil as it is in usa.
ive seen some programs listed as api but its not really an api..? you're only making requests to api so the name is a bit misleading. recruiters will think you're making an api, not a desktop app that outputs thing you read from an endpoint thats not even an api, but a json in a github repo
make an api and document it with swagger, use code patterns and all that shit. if you want to make front-end stuff (simple html with back-end code like templates), you can do it on c#, but i think its useless, no one uses razor nowadays.
if you know how to make an api with mvc pattern, you're unironically ready for a job, so learn it