May not reach maps because trial of chaos cruel ?

I finished the campaign and all side quests but one : trial of chaos in cruel mode, because there is no reward at all here.

It is optionnal right ? Since I don't have any quest ultimatum item...

I did absolutely everything else...

Continued my research and the problem may come from act 2 cruel. The "Montée en puissance" ( think it's called "Gaining power" or something like that in english ) is unfinished because i have "to talk to Zarka about I just found". But I have nothing to talk about and she neither. No quest mark, nothing...

You can ignore these quests related to Trials of Sekhema/Chaos in Cruel difficulty as they can't be completed (you can still do the trials for 3rd and 4th ascendancies when you obtain the required entry tokens in the endgame, but the quests will always remain).