I'm not from either country (Greece/Spain) and I think for anyone not from either country it would be difficult to distinguish between the accents especially from a low quality recording.
Also capt landing does not mean capt has to be PF for approach, could be monitored app.
All speculation and not really relevant.
I've spent years abroad and met lots of Spanish, Greek and many other (mainly European) people - speaking English. Agreed, with some parts I also found the accent of the pilot speaking to ATC hard to judge. But his accent is crystal clear in other parts of the comms, which leaves me with absolutely no doubt. Like when he says "Eh-sta-blissed-eh on se loca-li-sa...". The guy talking is 100% Spanish - and definitely not Greek.
As there seems to have been quite a bit discussion on who's voices are heard on the atc recording, I listened to it and can say with almost certainty, the first part until about 2.20" is Aristos, the captain, and from that point onwards its a spanish accented person, ie the F/O. I am Cypriot and I know a cypriot voice 100%, and I met Aristos years ago, may he rest in peace. Also, I heard this was one of his last flights with Flydubai as he was joining Ryanair, and based in Cyprus with his wife who was 7 months expecting. Another point, I thought the Russian woman atc officers' English was atrocious.