Surely Im Not The Only Person To Do This
I like to play one role specifically until I reach Iridescent 1 and then I swap to the other role. I dont normally go for a 50/50 type thing, I just finish one Grade and then move onto the other Grade.
Sometimes I start with Survivor, sometimes I start with Killer, depends on the mood.
Also one of the few times I dont get Iridescent on both roles... Ive been really busy with college... but hey, Im basically done with everything at this point which is nice.
(Also ignore my Account/Devotion, I moved from Console to PC and Im still trying to grind to get my Devotion up... trying to get my money up before I get my funny up.)

Comments
I would constantly switch between survivor and killer, trying to go up the ranks. It felt nice to reach Rank 1 with both.
I prefer to just get one out of the way.
It also gives me time to work on Archive Challenges since I can normally clear out all challenges for a specific role while I work on getting my Grade for that role.
Fair enough, I can get that.
Never cared much about the Archive Challenges, tbh. I like that they give BP, but sometimes I just forget about them entirely.