Past Simple: Comparison with “would” and “used to”

Past Simple can be used in the same cases as “would” and “used to”:

States:
Tom used to like his job but now he doesn’t.
Tom liked his job but now he doesn’t.

Repeated actions:
My boss would leave the office early every Friday.
My boss used to leave the office early every Friday.
My boss left the office early every Friday.

However, if something happened only once in the past we can’t talk about it with “used to” or “would”. We can only use Past Simple:

I started working here in 2017.
I used to start working here in 2017.
I would start working here in 2017.