Food for thought, since you want to be spoon fed.
100 15min in 25hours
100 hours in a week
100 4hrs in 20days
100 days in 5months
100 weeks in 2years
100 months in 9years
100 samples is not enough. So 9years is not enough time to confirm a monthly trend system, the same way 2years is not enough for a weekly trend system, the same way 5months is not enough for a daily trend system, and so on. Markets are giant fractals.
A trader overthinking their strategy is a laughable notion. Trading is highly complex and it will take a lifetime of creative thinking to reach superior optimizations. Most of us do not have the intellectual capacity to afford an issue as luxurious as overthinking something. Chances are you're not a genius, don't ever stop developing.
Read all my posts in this thread, connect the dots. You're welcome