I know this is a fairly late reply, but I hope I can still help you out.
I took a look at your casts (
https://www.warcraftlogs.com/reports/jd ... w=timeline).
You have very often moments where you don't cast anything for 4-5seconds straight. This is a huge dps loss especially for casters that reduce their own CD. I know sometimes there is a soak out of boss range but this shouldn't be as often at ur casts seem to suggest. (55secs into the fight for example).
There is a big mess with ur casts at 95seconds, 130s, 200s, 230s and more. All of these lead to very low uptime on the boss. You need to be able to perform your rotation while doing tactics, and not after you have dealt with a certain mechanic.
Furthermore when you have both an IL and Flurry proc, you should just ignore the FoF proc and use frostbolt > flurry > IL. Right now you seem to be doing frostbolt > IL > flurry > IL which makes you miss out on the shatter of frostbolt. At 77secs into the fight you miss the combo as well by doing frostbolt > flurry > frostbolt
Also, take a look at 41seconds into the fight for example. You cancel a frostbolt, only to shimmer afterwards and recast again. The power of shimmer is that u can use it while casting so you dont lose any dps at all.
Your 2nd pot should be used in combination with hero and IV and not 1min into the fight.
My biggest takeaway from this is that you have a hard time dealing with your rotation and mechanics at the same time, so try to practise it. Higher levels of m+ is a really good practise method for this since there is lots of stuff that can kill you, but you still need to pump out the dmg.