There is a flaw in your plan. You assume the money doesn’t continue to grow . If you earn 6% per year, you’d outlive your money with your plan.
If I need 100K per year and save 2M, but earn 6%. I’ll still outlive my money. No matter what age.
If I save 1.5M and need 100K, it will last 35 years. You need to adjust your formula to account for gains on investments to get a burn down rate.

initial $1,500,000
1 $1,486,779
2 $1,472,765
3 $1,457,909
4 $1,442,163
5 $1,425,472
6 $1,407,779
7 $1,389,024
8 $1,369,145
9 $1,348,073
10 $1,325,736
11 $1,302,059
12 $1,276,961
13 $1,250,358
14 $1,222,158
15 $1,192,267
16 $1,160,582
17 $1,126,996
18 $1,091,394
19 $1,053,657
20 $1,013,655
21 $971,253
22 $926,308
23 $878,665
24 $828,164
25 $774,632
26 $717,889
27 $657,742
28 $593,985
29 $526,403
30 $454,766
31 $378,831
32 $298,340
33 $213,019
34 $122,579
35 $26,713