Fertility Trackers worth the cost?

Have you tried any of these fertility trackers? What have you used and what is your experience with them?

I currently have Mira and currently regretting this purchase, I don’t feel it is very accurate. I want to see what everyone else’s experiences have been like with the other options? I regret not researching more before buying the Mira. From the little research I have done online in the past few days I am thinking Kegg would be the best fit for me. Are there any Kegg users on here?