Welcome. I used to live in Saarbrücken, but relocated to Switzerland. Do you know Luxembourg Homebrew Beer Club | Facebook ? The last post is from 2021, looks like Corona killed some activities, but maybe you still can ask and get some response.
You can also ask bar tenders or owners of craft-beer bars, they might know people.
Hope you find people, having a home brew club or fellow home brewers is a big part of the fun!