There aren't many words with the same meaning as slowly, but here are a few other words and expressions you can use, with example sentences:
1. lazily: avoiding hard work (often has a negative connnotation, but not always)
2. sluggishly: slowly, with very little energy
3. unhurriedly: in a relaxed and calm way
4. gradually (used for something that happens in stages, over a period of time)
5. at a leisurely pace: at a slow and relaxed speed
6. at a snail's pace (idiom with strong negative connotation): very, very slowly