D
https://www.canada.ca/en/immigration-refugees-citizenship/services/study-canada/work/work-off-campus.html
During scheduled breaks in the school year
You can work full-time if you’re on a scheduled break, such as winter and summer holidays, or a fall or spring reading week. You’re free to work overtime or work 2 part-time jobs that add up to a higher than usual number of hours.
You must be a full-time student both before and after the break to work full-time.
You can’t work during a break that comes before you start your very first school semester.
Ontario min. wage is $15.00 per hours now may go up to $15.50 later this year.
$15x20x4 =$1200 per month. I don't think you can survive on $1200 per month.
Will you consider a diploma in College?
It is cheaper.
Mortgage ? too far down the road
Federal Govt jobs are very competitive.
https://jobs.lovetoknow.com/Canadian_Government_Federal_Jobs
I retired from civil services. There were over 400 applications for 3 positions when I applied. Over 350 were Chartered Accountant (CA), Certified General Accountant (CGA) and Certified Management Accountant (CMA).
My advice is check out more possible options.
What if what you want don't happen?
U of T Master, policy/ financial analyst and Federal govt ?
You must have Plan B or Plan C etc.