Work permit at Canada Land border crossing

[RUZO]

Hello

I am a British Citizen, moving to Canada for work and was told that I can get open work permit when land in Canada as I have all the paperwork need like LMIA, health check and other document. I had to apply for ETA to board the flight but it is still inder review which means I cannot fly to Canada to get the open work permit.
I am thinking of going via America and request work permit at immigration there!
Has anyone tried this or has information regarding this!