So before Week 2 of Chapter 2 I was roughly rank 17-18, and this is me roughly playing 1-4 hours a day. After completing all the Assignments in Week 2 of the Chapter, I'm sitting at Rank 21 (20k~/64,000). If we were to do some quick math and assume that every Rank after 21 is 64,000 EXP you will need to accumulate about 1,216,600 EXP. If you were to do every assignments in Weeks 3 and 4 you will only get 307,800 EXP (not including assignments unlocked from Ranks). Leaving you about about 800,000~ (880,800) EXP for you to grind out to hit Rank 40. I don't know if this is intentional or what but even with me playing 1-4 hours a day, that's a hell lot of EXP to be trying to earn after completing all the Assignments, and this is only assuming that all the Ranks after 21 are 64,000 EXP.