Starting a new job soon but still applying

Hello, as the title says, I've been job searching for a while now and finally received a job offer to start next month. It's not really in my wheelhouse but need to pay my rent. I am still applying to other jobs postings that are more in line with my interest and experience and have 2 interviews coming up and will still prepare for them as best as I can. If for some miracle I receive a job offer, is it ethical or legal for me to accept the 2nd job offer? Will the word get out and my name could be black listed? My contract with the 1st company does state that I can give 2 weeks notice if I decide not to join their company even if I have already signed the offer. They also in turn can terminate my employment if I don't pass probation after 3 months. I also have completed the on-boarding process. I live in Canada British Columbia in one of the metro cities. I wouldn't mind hearing from recruiters, employers and employees so I can hear all sides. Thanks in advance.