Allah has not created Iblees as a Shaitan but he himself shows the nature of evil. Allah has not created evil as an evil itself but He has given both power of act and at the same time many ways of guidance. Now if Human or Jinn are not choosing His guidance as a tool to guide themselves for sure they will go astray. For example if you do not take food, our bodies will become week and we will die because our body needs physical energy as long as we are in this material world so if someone complains why his body became weak what would be your reply? Same that because he didn’t take food. Therefore we humans by default have both nature of good and bad ( Nafs e Ammara and Nafs e Lawama and Nafs e Mutmainna) but on top of Nafs e Ammara we have strong intellectual power of understanding and a strong system of guidance in the form of “Vahee” Revelation brought by Prophets. Therefore even if Shaitan was not there, we would do mistakes if we do not use our intellect and guidance of Allah which He has sent through His Prophets.But of course Shaitan takes it as a good opportunity when a human being shows weakness in his own determination and dominates his wild nature (Nafs e Ammara) over his Intellect and so he does any mistake but Shaitan is not the primary catalyst for any sin rather it’s our own soul. Yes Shaitan portrays evils in a good form to attract us but finally it we who has to decide to select. Same in the case of Guidance there is no compulsion otherwise if Allah wants no one could do anything wrong but again then there was no role for Human to become void or bad by his own choice and in that case will loose our nature of free selections. Also it’s not true that we go astray just because of Shaitan only otherwise if this was the case all Human would say Allah on the Day of Judgement that they have done all the mistakes because of Shaitan and they had no role while it’s not true.