There are no more Play-off rounds for those finishing 4th in the Italian Serie A. All 4 clubs are automatically qualified for the Champions League. The rules were the same last season as well.
Yes, it is not wrong from the 2018/2019 season ucl Serie A slot is 4 clubs. They are rated as the third best league based on UEFA coefficients, so automatically get 4 slots to UCL. So it looks like Milan, Inter Napoli and Juventus are ready for the UCL 2022 season.
There is still one game , Milan and Inter still have a chance of winning. It seems that the last game is not a strong opponent and Milang is 2 points ahead, maybe Milan will win Serie A this season.
Source:
https://en.wikipedia.org/wiki/Serie_A