Assalamu Alaikum. Is it kufr if someone praises himself and thinks he is superior to others for committing a sin? And what if he thinks that he is superior to others for being better at this sin? Is any of this kufr? Jazak Allahu khairan.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

A person does not disbelieve by committing a sin or by committing it openly as long as he does not consider it as lawful.

However, if he considers such a sin as lawful, then he goes out of the fold of Islam.

Merely boasting of his sin to other dissolute people and considering himself as skillful and superior to them in committing it, is not counted as considering such a sin lawful; hence, this mere act is not considered disbelief.

Allah knows best.