Canada has an extremely generous, massively exploited foreign worker program (it is actually one of the reasons this government is profoundly unpopular). ByteDance, like every other company, can unilaterally declare that they need to bring in an entirely foreign staff and get it rubber stamped. Given the company's alleged closeness with the party, using it as an easy vehicle to drop loads of intelligence workers of various sorts in Canada would be logical. Similarly China has a thing with running intimidation tactics against Chinese ex-pats living in Western countries.