Hi, I can tell you where The Apollo apartments are, but I have never stayed there, always been to Costas Chrysoulla. The Apollo apartments are immediately due north of Costas, on the same small side street off the street that comes from the seafront toward the countryside. It was quiet there when we visited this October, but in pst years, in season, it always seemed lively. Got a pool and bar, and, like Costas, very close to everything.
Olympic must have only just added this place in the last few days, probably a reaction to reduced capacity elsewhere, The Apollo would be somewhere I would seriously consider, along with Manolis apartments, but the latter is not in Olympic, only if you go indepenently, which is easy, given that Olympic only use Easyjet, you can book yourselves, and that no transfers are included, so a 220 euro return taxi (from Zak) is also needed.
Hope this helps.