Hello guys. I'm transcribing this beautiful song that consists of piano and strings but some parts of the song don't sound like they're following a fixed tempo.

Heres a link to the song.


Im interpreting the intro to this song as 3/4 at a tempo of around 115. Sometimes the intro implies a certain BPM but then it changes shortly after.

How should I approach notating music like this if I want to be as accurate as possible without losing clarity?
if the tempo changes entirely just indicate a tempo change. if they're holding or slowing down on particular stuff put a fermata. or just indicate ritard/rubato and a tempo when they come back.
Thanks Primus.

Some parts of this song do feel like they slow down but another thing I noticed is that in some parts it feels like it speeds up temporarily. How would I notate this?

Another question related to notation.

In one bar of this song there is a whole note starting on beat 1 with quarter notes on beats 2, 3, and 4.

The whole note rings underneath the quarter notes but I can't notate it as a whole note or else I won't be able to fill in the notes in the rest of the measure. How do I notate this?