Asking earnestly: is ArXiv a valuable resource? I used it few years back when finishing my (late) Master's, but also saw a lot of crap published there (primarily for promotion/visa purposes) so it kind of took the shine out of the service for me.
More to your question, I recommend something like semanticscholar to find actual relevant papers. Try to identify researchers that seem trustworthy, then explore the citation network around them.
For more hot off the press stuff, follow what gets boosted on social media.
Still doesn’t cover the truly niche stuff but it’s a start
I don't think you fully understand the problem. It doesn't matter if you can find in arxiv a preprint of an article published on a reputable journal. What matters is that right besides that paper you will find a dozen other papers that can be utter nonsense generated by a poorly calibrated slop factory. You don't find those in papers published in respectable journals which enforce double blind peer review and were filtered for relevance and quality.
It's that peer review process that creates value and relevance. Otherwise all you have is a glorified file server.
It's not peer-reviewed and supposed to free and accessible from both sides so the results kind of makes sense.