New on here, but I took a look at your logs which I’ll discuss but I also wanted to recommend Healbot Continued addon which is what I use and I really saw my HPS increase when I started using this addon. It takes away that extra step of clicking on a raid frame and then clicking the heal or using a key binding. I have the majority of all my spells set up to be used with variations of Shift+left mouse click, Shift+Right mouse click, Shift + Middle Mouse click, Ctrl + mouse 1,2,3.. etc… just an idea of how you would use healbot.
Now let’s discuss your logs.
Looking at what legendaries you have as well as your trinket use etc. I noticed on the first boss fight of NH, you only casted Healing Surge once.
this should be casted a lot more especially with legendary bracers. The best way to use this is to pre cast this spell on tanks or even throwing a spot heal to a raid member, if they are full I would jump to cancel the spell or move and then cast another precast until I can get it to hit where it’s used, but also if raid damage is occurring to stop and react according to the damage.
Since it looks like Chain heal is your number 1 healing spell for all your logs, I would recommend specing into High Tide instead of Ascendance.
Also I would spec into Deluge instead of Ancestral Guidance.
With your tier set bonus, which benefits Healing Surge and Healing Wave also. These spells need to be used more period.
Also communication with the other healers to stagger major healing c/ds during increased damage phases will help your HPS so that you are not overlapping c/ds
I hope this helps 🙂