RAV allows interim work as self-employed for 12 months for those up to age 45 (and for the entire length of qualified period for those over 45). The RAV Zurich special office for self-employment has this relevant comment on its website (translated):
"In the course of your job search, you may receive an offer to work for a limited period of time, but not as an employee. Instead, you may arrange this activity with the client as a self-employed person. This can be considered as a self-employed interim income that you must declare to the unemployment insurance fund."
https://www.zh.ch/de/wirtschaft-arbe...tml#2114010240
Although RAV is supportive of such activities, the difficulty may come with the SVA social security administration which normally does not consider self-employment to involve only one or two clients. Then it is often necessary to engage a payroll service as the legal employer, or to buy or set up a legal entity to employ the contractor (probably not suitable for short-term "self-employment").
In the first meeting with the RAV adviser it would be advisable to discuss the possibility of working as a contractor for a client. The RAV adviser may then outline the next steps on how to proceed or will possibily send you to the Zurich Fachstelle Selbständigkeit (which, btw, appears still to be closed due to Corona).