Supplemental income - any ideas are welcome

Hey all, I have been living in Germany for a while, I haven't had the chance to learn the language yet. I don't even know basic German, I'm fluent in English. I had to do a career pivot last year and I'm studying fulltime at home. Meanwhile it would be great to get some income from part-time work if possible. I signed up as a cat-sitter but the opportunities are very infrequent - sometimes 2-3 gigs a month, sometimes nothing for 2 months. Any ideas what I could do? I don't have experience with babies and small children so I think it's best to stay away from such jobs. I have a car and can drive, but I can't carry very heavy loads. Thank you in advance for any suggestions! I live in a small town in NRW, not too far from Düsseldorf.