That was my understanding also, an ICAO ATPL holder can self certify and just go sit the exams at their leisure, but what I wasn't aware of is the 500 hour requirement on type. From some further reading, it's 1500 hours total time with 500 multi crew, but it doesn't state 500 hours on a specific type. I have well over 500 hours multi crew at this point but on various 2 crew airplanes. Here is some info I found
https://www.executiveflight.nl/wp-co...conversion.pdf
and here
https://egnatia-aviation.aero/traini...s/conversions/
So the steps in a nutshell then are 1) EASA class 1 medical, 2) 13 ATPL exams (I read in the last couple of years that VFR/IFR Comms have been merged into one exam, I could be wrong), and 3) a skill test on whatever you are typed on (and presumably current is most logical). So it's a matter of cheaper country to write the exams and then how much a skills test would cost depending on availability