What does the status "under editor evaluation" entail after a 4-month review phase?
According to this answer:


  The status "under editor evaluation" indicates that the paper is now with the Associate Editor (AE) who will evaluate it based on the reviews and decide whether the paper should be accepted, rejected, or revised. However, the AE's decision is not final: he/she can only give a recommendation to the Editor-in-chief (EiC) in this matter. The final decision is taken by the EiC. This is when the status changes to "decision in process." Thus, to put it simply, "under editor evaluation" means that the paper is with the AE, while "decision in process" indicates that it is with the EiC.


Also see:


the Elsevier's peer review process, 
and this answer: After with editor the current status is submitted to journal