If Sinkieland were a civilized country, there would be term limits, and 'looking for a successor' would be a non-issue. The people will decide, not you. You are not a monarch.
When you have recruited a bunch of untrustworthy PAP PAPER Generals and cronies whom you knew too well that will plunder this country for the same reason they joined PAP camp for the money, there is literally no one (within your own camp) whom could be trusted nor feel safe to succeed you. Even the current president is castrated by the couple, and forced to take up the role with no legitimacy.