I did solar with mu warlock. Hardest ever yet

Get the kills in cruicible mayhem. Each kill is 1%. Way faster than killing adds. Speed you finish depends on your character. I did solar with my titan in 40 minutes. Void hunter took longer.

It depends on the character. Every subclass which has access to a grenade exotic, giving you grenades at respawn, make it pretty easy. You'll have to wake the hive a lot of times, but you can throw a grenade, suicide, let a friend revive you, etc. You'd be finished in around 15 runs of waking the hive. However, where I will agree is that it's a very grindy quest, and that the material collecting was the most mindless thing I ever did in Destiny, since farming hadium flakes. Which in return must be the dumbest activity, since farming for weapon parts. I personally know of no Y1 equivalent, that was as mindless and time consuming. Maybe the Loot Cave?

What class are you playing it with? For the search of materials use a ghost, still it takes about one to two hours and that part is definitely stupid. I did my solar kills on the first moon mission "dark below" as a hunter. GG with combustion and explosive grenade worked quite well.

You feel it's a grind? Trying getting 500 void ability kills as a Titan.....

The kills are easy, it's the gathering one that needs... an ultimate patience. Somehow leaving the game for a few days and come back raises up the RNG, might've been my imagination but that's how I got the mats done.