Vals
sub-designations exist:
- vals criollo
- vals peruano
Vals or tango
From a talk about the genre of Guitarra mia performed by Hugo Diaz
Look at the first 0:20 and last 0:25 of "Amores estudiante" - you can say the same thing. And relatedly some milongas by various artists as well - there are parts in between that feel more like tango. There are more periods of elongation of the rhythm in "Amores estudiante", it's true. Nonetheless, it seems pretty hard to me to argue with that 3/4 time that "Guitarra mia" keeps coming back to, which (in my view) is what defines a vals fundamentally. Perhaps you feel that the classification is instead based upon a global view of how the song feels.