I tried to solo that conquest, but no dice, wizard spells are too shitty in coverage to hit every mob, even like disintegrate is too short to hit from one spawn to the other, and using ranslor tornados to pull stuff in the middle worked well but it takes too long. I did the event with a few different specs like 5times, always 310-320kills only.
Ended up not doing that conquest in the end, I did GR75, 3gems to 65(which is a journey step anyway) and all bosses in 20mins. All bosses was actually easier than I thought, only took 16mins on my first try and I didn't even get that good RNG on act5 bosses, I cleared them in 6mins when on the quick check I did before to see if it was doable I did them in 5mins instead. GR75 was kinda easy, I just got stuck at 71 with shitty RNG for a while, failed 71 9times, then I cleared it with so much time to spare I unlocked 73 right away, and did the rest in one try with decent rifts.
Now just need to find someone powerlvling on HC EU to finish the season journey. Fuck wizard though, not playing this again anytime soon unless they do massive changes to the set playstyles.