Tax Year Prior to 2020: I have a foreign income on a T4 form (Canada). Am I supposed to enter that pretending it is a W2?

No, don't enter it as a W-2.  You will enter it as Foreign Earned Income.

Here's how to get to that area:

1. With your return open in TurboTax, search for foreign earned income and then click the "Jump to" link in the search result.
2. Answer Yes that you earned income in another country.
   
3. On the next screen select you received A statement from my foreign employer.

Another answer also mentions that you need the Deluxe Edition to do this, because the free one doesn't include Form 2555. Is that correct?