I purchased a keyboard 2-3 months ago. I also followed a course on Udemy (Pianoforall). Not sure if you are talking about the same course. The songs played may be unfamiliar but he teaches how to play a generic melody and then for practise shows how to play some songs (Does not require you knowing the song, just go with the melody of the song). I completed like 20% of the course and started watching youtube videos of the tutorials of the song (I could not resist playing songs on the piano). I was able to play songs, starting with simple one hand songs. I wasn't able to dedicate much time but still I can play Mozart's Turkish March, We are the champions by queen, faded etc. This is after I followed only 20% of the course. If you complete the complete course, I am pretty sure you will be able to play any song you like.
Youtube channels:
https://www.youtube.com/channel/UCts9lFixyOqwhGCEbXErPwA
https://www.youtube.com/user/PianoLessonscom