EWCM for 4 days but no positive OPK

This is our second month TTC for baby #2 and my first time ever using OPKs.

Because of my work schedule, I can only test 1x/day in the evenings on weekdays. The test line has been pretty faint throughout the last week of testing, but I have definitely had EWCM since Wednesday. We BD yesterday (Friday) and Tuesday.

Is EWCM more accurate than OPKs? Or other way around? Is it that common to miss the peak if only able to test 1x/day?!