I believe we can work after 120 days according to the information here:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/temporary-residents/study-permits/post-graduation-work-permit-program/permit.html
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/temporary-residents/study-permits/post-graduation-work-permit-program/permit.html