First of all,this does not go against his mightiness,Allah SWT rejected the premise he has a son,and you need a wife to have a son as Christians call Mary the mother of God,so basically Mary is God's wife in Christianity so Allah SWT is saying,he cannot have a son because he doesn't have a companion,he DOESNT NEED A companion,read Surah Ikhlaas.
and also,Sons are for successors and Humans,not for God,And wives are for Humans who need Sexual pleasure,not for God,so therefore God cannot have any son or wife,because God doesnt need pleasure or Successor,God is the Eternal.
as for the second claim,No it doesn't limit his mightiness,what does limit his mightiness is the Bible saying God couldn't tell the fig from its season,thats whats limiting Gods knowledge afcourse,if God is eternal he doesn't need a son or a companion,so therefore having a son and Wife is contradicting God's VERY NATURE,the one who always existed.
so this baseless,stupid claim really needs to be repelled by Christians because they have no excuse,they have to convert to Islam,even atheism is dying out so Atheists are desperate to grow a New atheist community to try and target Jews and Muslims,and almost 98% of the time they fail,their claims are refuted,etc,etc same with Christians.
