Canada side: Travel restriction still apply.
https://www.canada.ca/en/public-hea...us-infection/latest-travel-health-advice.html
If you want to reenter quickly then you will have problem entering at the border asking why you want to travel without any necessity or might have to quarantine for 14 days.
US Side: If you are currently on B status then reentering on B will be questioned as B is not for frequent entry. If you are not on B status then B visa is not going to help reenter. If you share your specific situation then we can share our knowledge and experience on reentry.