The only way a manager should be taking any portion of any tips from a customer is if they are the sole worker serving that customer. They are not entitled to tips earned by subordinates, even if those subordinates have a tip sharing arrangement.

That is correct, if your manager is not also the employer (except in limited circumstances).

https://www.ontario.ca/document/your-guide-employment-standards-act-0/tips-or-other-gratuities

Managers are allowed to keep the tips and gratuities they receive themselves, and generally may participate in tip pooling arrangements if their employers’ policy permits them to do so.