Conflicting dates for ovulation between 4 apps?!?

Sam

So I will start by saying I have tested for ovulation I every day since I stopped bleeding and I haven’t had a positive (but I never do, I have had it tested at the doctors and they have told me I ovulate but for some reason the LH strips don’t work for me)

FLO is saying I was fertile between 14-23 of February with me being most fertile on the 20!

GLOW is saying I was fertile between 17-23 of February with me being most fertile on the 21!

OVIA is saying I was fertile between 20-25 of February with me being most fertile on the 23!

KINDARA is saying I was fertile between 20-24 of February with me being most fertile on the 23!

I have put all the same information into these apps for the past 6 months so I’m very confused right now!!!