Need Sona Support Help

I haven't played in over a decade, and I'm starting again, but I haven't been able to get the hang of it really. I've been playing Sona cause I sort of mained her previously, and her ult seems a little too short lived, her q seems a little lower damage and just a little too short ranged, her heal doesn't seem to do much, her move speed buff doesn't seem that significant, and in short everything doesn't necessarily feel unplayable, but I feel like I'm never in a position to significantly affect the outcome as my abilities are always just a little too insignificant. Part of this I'm sure is my own reduced ability, and unfamiliarity with items and all the changes, but early game I feel like I'm missing just enough oomph to really make a difference, and late game, even with full items, I feel I'm not really contributing much to team fights. My ult can disrupt other ults, or keep enemies stunned for a moment, but outside of that I don't feel I'm doing much of anything and if I die, I feel I'm just feeding the enemy team and making things harder for my teammates.

Can anyone give me some tips to improve, or let me know if Sona is just in a not great state right now?