You do not have to trick people into accepting Islam, you do not have to make covert da’awah. It does not work to Ingratiate yourselves to the Kuffar so that they will listen.
You try to tell them that Islam is so similar to what they already follow, and you do this so they will respect you and you cannot see from this that you are enacting the ayah:
وَلَن تَرْضَى عَنكَ الْيَهُودُ وَلاَ النَّصَارَى حَتَّى تَتَّبِعَ مِلَّتَهُمْ
No, Rasulullah ﷺ was not less confrontational in Makkah than he was in Madinah, indeed, it was in Makkah that the fundamental confrontation was established.
The essence of the Da’awah in Makkah was:
‘You are wrong, your fathers were wrong, you are liars and sinners and you are in total darkness, and unless you repent and accept Islam, you are going to burn in the Hellfire forever’
How, I wish I knew, do you expect Kuffar to change if your whole approach to Da’awah is to reinforce the kufr they are already upon and to assure them that Islam is only slightly different?