I daven for the ammud a decent amount, and try not to sing too much. I use mainly nusach, not tunes that I’m attaching to words.
I’ve actually gotten complaints at times that I should sing more, but I refuse.
The only times I’ll use songs are for Lecha Dodi, Kel Adon, and during Hallel, for Hodu and Pischu Li. For other things, I’ll use the proper nusach.
I daven for the amud somewhere on Yomim Noraim, and I don’t sing too much. I sing some, because my Rosh Yeshiva once said that you should. He said he asked his Rebbe, R’ Shmuel Berenbaum zt”l about it when he started having a minyan in his yeshiva for Yomom Noraim. In the Mir, they don’t sing at all, as far as I know – just nusach.
R’ Shmuel zt”l told him that he should sing, because people today wouldn’t be able to handle the davening without it, they’d just lose their minds.
Because of that, I sing a little bit, during a piece – but almost never the whole piece. Nusach is there for a reason.