I saw an ad that said most CO detectors like the ones I use below do not actually alarm until 70 PPM which is already a dangerous level.

https://www.amazon.com/dp/B000Q5VMKG/

Are there better ones out there I should be using that alarm at lower levels?

I have a Kidde. My understanding is that they aren't necessarily set at 70 ppm but that's where they're tested and certified at.

Also my understanding that 70 ppm can be dangerous, but mainly at prolonged exposure, or if you have certain health conditions.

I have a big boxstore one, likely Kidde, but also have a Mila air purifier that has CO detection. For what it is worth, when I click CO the alert level has three levels of "alert"

Moderate - 70ppm states Exposure duration at 4 hours,
High - 150ppm - Exposure duration 50 mins
High - 400ppm - Exposure duration 15 mins

Most of us only worry about gas flames & maybe fireplaces, sooooo
if you have a specific source of concern, Google might suggest The One to monitor that.

I am not going to pursue the comical thread of what humans/animal contribute to indoor CO2 here but ... hahahaha? ... but you got loads of babies & older dogs inside?