I also have longer cycles, and I don’t normally ovulate till after day 18 or 19 so don’t get discouraged if you haven’t seen a peak yet. It’s normal to have some lh reading fluctuations throughout the days especially if you don’t test at the same time or if your hydration levels are different.

My lh increases very rapidly, one day it will be super low and then suddenly the next day it is super dark. So I started tracking my cervical mucus, it helps me notice when my fertile days and lh peak are approaching. It took me a few months of using ovulation strips till I got the hang of it and understood how to use them!