https://www.realityblurred.com/realitytv/2022/01/american-idol-season-20-5-numbering/

For its first four seasons on ABC, the network touted each season as "Season 1," "Season 2," "Season 3" and "Season 4" -- with the qualifier that each season was number based on being "on ABC." (https://twitter.com/AmericanIdol/status/1261351774184632320) But since this year is not only the 20th anniversary of Idol's launch on Fox but the 20th season overall, ABC has embraced "Season 20." Last month, the Idol Twitter account even tweeted that the show is returning on Feb. 27 for "the historic 20th year of #AmericanIdol on ABC!" (https://twitter.com/AmericanIdol/status/1466488392879788033) "So yes, we’ve gone from season 4 to season 20 in one year," says Reality Blurred's Andy Dehnart, who adds that "this wonky numbering is indicative of a larger problem." Not only does ABC's previous numbering erase the Fox seasons, but "this does introduce a real problem," he says. "Giving the same numbers or titles to different seasons is just freaking confusing for those of us who are, like, trying to find TV shows to watch."

If they were going to duplicate seasons they should have retitled the show. They could have just added II on the end, even.

Most rebooted shows just resume. Dragnet, for example. I think Roseanne did that too, and probably Will and Grace.