Guild Wars 2

I don’t see the problem really. I got both on the same try and it was only my 2nd time fighting the hologram. And I didn’t use any afk by the wall tactics.

The secret to getting them is simple patience.
What I mean by that is not to try any heroics. For example trying to dodge through the scorch marks as they are too wide to do so without getting hit.
As for the right attunment thing you need a weapon which auto attack can only hit the target. And of course patience again. In other words I didn’t wait till the last straw to stop attacking but instead I stopped when my attunment had less than 10 sec left. I also turned my back on the hologram to make sure I’m no longer attacking and then clicked the floor to stop targeting it.
Once the 3 colored holograms spawned I started using only my scepter’s main attack. Yes this is the time you have to use the taget only weapon attack. Otherwise you will run a risk of hitting the 6 elite holograms in a crossfire when you move to the next color. Same as with the part with the Prime hologram I also stopped attacking once an attunment had less than 10 sec left. There appears to be no need to avoid the attacks during this phase as I did get hit by a few here and still got the achievement. So obviously only attacks during Prime and Ultraviolet phases count.
And in the final phase I avoided the attacks of the small holograms and any of the colored attunments on the floor. The charge attack of Ultraviolet also doesn’t seem to count against the achievement as I got hit by it too.

And thats all there was to it. So just calm down and don’t try to rush things and you’ll be fine.