The final two sentences of the first paragraph lack reliable source(s)
resulting in the renaming of NERIT to ERT; ERT began broadcasting once again on 11 June 2015." - Try not to have the last word of a sentence start the next one like this
"The Greek broadcaster has used various methods to select the Greek entry in the past," - nation's
The entire third paragraph in this section requires reliable source(s) to verify the information contained within it
"From 2010 through 2017," - sounds awfully AmEng, how about to?
Internal selection
"the Hellenic Broadcasting Corporation (ERT) announced" - the full name isn't needed since it is mentioned in the previous subsection; just the mention of the acryonms will suffice
At Eurovision
"On 28 January 2020, the allocation draw was held," - how about adding where exactly the allocation draw was held?
"Fokas Evangelinos was hired to organize" - should be organise since it is a European contest
"choreography for the performance.[11][2]" - refs in numerical order please
"the best-placed in each semi-final advanced to the final round." - best-placed entry or best-placed country
References
References 2 and 12 is missing the publisher of the article
Reference 4 is missing the agency who provided the story to Deutsche Welle
References 8 and 11 are missing the dates the articles were published
Reference 9 is missing the author, publication date and the title should be in the language it was written with the English translation in the trans-title= field
The title of Reference 12 should be in the language it was written and the English translation in the trans-title= field
The final two sentences of the first paragraph lack reliable source(s)
resulting in the renaming of NERIT to ERT; ERT began broadcasting once again on 11 June 2015." - Try not to have the last word of a sentence start the next one like this
"The Greek broadcaster has used various methods to select the Greek entry in the past," - nation's
The entire third paragraph in this section requires reliable source(s) to verify the information contained within it
"From 2010 through 2017," - sounds awfully AmEng, how about to?
Internal selection
"the Hellenic Broadcasting Corporation (ERT) announced" - the full name isn't needed since it is mentioned in the previous subsection; just the mention of the acryonms will suffice
At Eurovision
"On 28 January 2020, the allocation draw was held," - how about adding where exactly the allocation draw was held?
"Fokas Evangelinos was hired to organize" - should be organise since it is a European contest
"choreography for the performance.[11][2]" - refs in numerical order please
"the best-placed in each semi-final advanced to the final round." - best-placed entry or best-placed country
References
References 2 and 12 is missing the publisher of the article
Reference 4 is missing the agency who provided the story to Deutsche Welle
References 8 and 11 are missing the dates the articles were published
Reference 9 is missing the author, publication date and the title should be in the language it was written with the English translation in the trans-title= field
The title of Reference 12 should be in the language it was written and the English translation in the trans-title= field