As of September 2020, on all major platforms . When you see "Season 1," it usually refers to the first season of the game's "Free to Play" era, which reset the seasonal count.
When you download the game today, you aren't getting a "lite" version—you’re getting the full experience: Rocket League Season 1 Free Download
Rocket League: How to Download and Play Free (Season 1 & Beyond) As of September 2020, on all major platforms