If you look at many other cultures, e.g. African mothers carrying their babies on the back. They don't have need for diapers. What many people in the west where we have been so trained on diapers don't know is that babies can be potty trained very early (<3 month). There are quite a few resources on this (search for infant potty training).
Have you had success with this? I was aware of this when I became a parent but it was impossible to find the space or energy amongst everything else.
Also, where in Africa?
I read several books on this topic but had no luck until about six months in. I also never tried the bottomless for a day or week approach so
With the hope of receiving a reply with proof....
There is absolutely no way a 3 month old is potty trained. As in, the 3 month old infant can communicate and use a toilet. They likely can't even hold their head up at that age.
https://www.babycenter.com/baby/diapering/infant-potty-train... indicates that a potty can be introduced from 4- to 6-months old. Potty trained by 18 months is much more reasonable.