How can I search x1337 probably?

Do you mean properly?

I've found 1337x's search engine to be a little special. It's very prone to giving zero-result searches if you over specify your search terms especially with how variable some people can be when they post torrent names and tags.

Search for "qxr" with zero other qualifiers and make sure it reports something. Then start narrowing it down with additional terms and backtrack once it gives you no results.

Try searching for qxr and filtering from there. Find a result from one of the uploaders you like, click their name to see their uploads, and save the page as a bookmark for next time 👍

You could try a search aggregator such as qbittorrent search or snowfl.com

Setup the ARRs(Sonarr, Radarr, Lidarr) and connect them to your torrent client

i usually search the name and "QxR".