You can find decent papers from some well known conferences. Just search for something like "top tier conferences <topic>" and then "<conference name> 2026 accepted papers". Reason why that app gets you pre-published articles is because it's using arXiv. There's conferences for every little topic, and even within computer science (hardware security, software engineering, usable security, etc). IMO conferences with IEEE or ACM in the name are pretty decent. Can't say they are ALL good, but still, it's a good starting point.

Fmhy has a section on papers, basically you can email the paper authors and ask for a copy (that's what research gate does), pirate the paper, or use a library subscription (like your local library) to get access to paywalled papers