Need some help please!?!

Hello there ladies! So I have 4 period ovulation tracker apps Glow, Get Baby, OC and Tracker. Here are the dates they say for my fertile window and O day this month....

Glow, fertile window 20th-26th O 25th

Get Baby, fertile window 23th-30th O 27th

OC, fertile window 21st-26th O 26th

Tracker, fertile window 22nd-28th O 27th

So...based on this give me your thoughts when exactly should we DD? I am not one for using the test sticks so just thought I would see what everyone thinks!! Thanks ladies for your input and thoughts!!