Hello Andrian,
I am also amateur and beside ending button, sometimes I use the fade out button.
I am doing that if the ending button doesn't sound aproppriate for that particular song or it is hard to synchronise my playing with ending 1.
(You better press some fill ins before you press the end button)
Endings 2+3 usually got a melodic part in preset styles that doesn't match with the melody of the song that you are playing and I don't like to use them,or delete the melodic parts.
But sometimes you can use them if you start the song with intro 2 or 3 and in the middle of the song you press again that intro's so when you use ending 2 or 3 the melodic will not sound "strange" to the listener.He allready has listened to it.
Some keyboard players gradually reduce the tempo untill it ends.
(I find it harder than the other methods for an amateur while you have to continue to play the song)
The proffessionals I guess they like sometimes to use arpeggios over the last chord for ending.
And all I know is that (unless you use the fade out button) you better finish the song in the main chord of the song which most of the times is also the first chord of your song.
(the song is in the Cm scale, your last chord better be Cm)
As I allready have said, I am just an amateur(noob
) and I would also like to see some advices of our experienced keyboard members.