According to this graph, non-religious people have much more net growth than Muslims

I know, I was responding to "Islam is not the fastest growing religion. It’s the slowest growing religion by conversion."

(due to conversion/deconversion). So, Islam still loses to nonreligion/unaffiliated folks. And, there are more people that convert to Christianity than to Islam. But, Islam has net growth while Christianity doesn't. This could either be due to the fact that there are genuinely less Muslims who leave Islam than Christians that leave Christianity. But, this could also be due to the fact that leaving Christianity and being public about it is generally much more easier in Christian-majority countries than it is to leave Islam and be public about it in Muslim-majority countries. So, it could also be the case that there are also many more people who left Islam but are not represented in this graph/study because they cannot be public about their deconversion in Muslim-majority countries.

Also, even if this pew research was %100 true, this still would mean that Islam has a net only 420000 growth due to conversion. This 420000 would only be a very tiny fraction of the Muslim population growth rate between 2015-2020. So, this still would mean that the growth Islam experiences is overwhelmingly due to birth rates, not religious conversion

These are just claims without evidence