According to the below link under "Beendigung des Arbeitsverhältnisses" (Ending of the employment relationship), the earliest the termination can occur under a mass layoff is after 30 days, except where the contract or law causes it to take effect later:
https://www.zh.ch/de/wirtschaft-arbe...iessungen.html
Then click on "Merkblatt Massenentlassungen" at bottom for source and more information.
Also, to avoid sanction days at RAV Swiss job service, you should begin searching for a job as soon as possible and document your efforts, at least 10 to 12 applications and other efforts per month.