Advanced slowly is a phrase that can be easily replaced by several synonyms, depending on the context and tone of the sentence. For example, you might use phrases like "proceeding gradually" or "moving forward steadily" to describe a cautious startup. Alternately, you might choose to use "incrementally" or "systematically" to indicate that progress is being made in a precise and measured way. Other options could include "slogging ahead," "inch by inch" or "creeping along," all of which give a sense of slow but steady progress. Ultimately, the choice of synonyms for "advanced slowly" will likely depend on the overall mood of your text, as well as the specific meaning you are trying to convey.