Wall has difference of 3cm at one end can it be skimmed level

[Donnapaddy]

Hi had extension done and when we measure the wall at each end their is a 3 cm difference, can it be skimmed to match as our units are going on that wall , also the render outside is too close to our door and hinges are cracking it , can this be trimmed back at all will add pics below thankyou

 

[Donnapaddy]

Pics below

 

[joe-90]

Yes to both of those.