Hello,
Here is a list of the toughest JEE Main question papers from the past years based on student reviews and expert analysis. These shifts are widely considered the hardest because maths was very lengthy, physics was tricky, and chemistry had unpredictable questions.

For 2024, the toughest papers were 4 April Shift 1, 8 April Shift 2, 9 April Shift 1 and 6 April Shift 2.
For 2023, the toughest papers were 29 January Shift 2, 30 January Shift 1 and 1 February Shift 2.
For 2022, the toughest papers were 27 June Shift 2, 28 June Shift 1 and 29 June Shift 2.
For 2021, the toughest papers were 27 July Shift 2, 25 February Shift 2 and 16 March Shift 2.
For 2020, the toughest papers were 7 January Shift 2, 9 January Shift 1 and 6 September Shift 2.
For 2019, the toughest papers were 10 April Shift 2, 9 January Shift 1 and 12 April Shift 1.
To get the question papers for JEE main check the below link for (2016 - 2025):
https://engineering.careers360.com/articles/jee-main-question-papers