we were obliged to pay the 2 years of loan (last year and this year). then if those conditions will be met during this season (2022-2023) it will become an obligation to buy, otherwise we can decide to give him back.Kulus deal was an obligation but it came forwards in time if those conditions were met, we were always obliged to pay (as I have seen reported).
Lo Celso was an option with a high initial loan fee, we could have walked away.
for zaniolo I guess we have proposed the same type of deal, but roma want the money right now not next year if some conditions will verify (because they know zaniolo is prone to injuries)