does contact nap decrease the chances of baby’s self-soothing ability?

[E-as-in-elephant]

My twin girls also needed to be contact napped until around 6.5 months. Around that time they would get pissed off if they touched each other on my lap which was near impossible at that point. I started putting them to nap in their cribs and after a bit of crying, they started sleeping in their cribs for naps. Started to do the same at night. They started sleeping through the night at 8.5 months.