The most amount of RP you can get in a week is 13,000 and you suffer a decay of 20% per week of your current RP before adding in how much you earned. With this is mind:
Week 1: 13000(Rank 4)
Week 2: 23400(Rank 6)
Week 3: 31720(Rank 8)
Week 4: 38376(Rank 9)
Week 5: 43700(Rank 10)
Week 6: 47960(Rank 11)
Week 7: 51368(Rank 12)
Rank 12 is when you get your first 3 pieces of epic gear, meaning it is mathematically impossible to get it before the 7th week.
This also assumes you got CP in the top 0.1% EVERY week for 7 straight weeks. This is the mechanic that makes the grind for R14 so brutal.
If you aren’t playing that much, it will take you much longer. On top of this, you can’t get past rank 11 without being in the top 1.4%.
You’re acting like getting this gear is far easier than it actually is.