Sheikh if a born muslim committed kufr act and repented from it and returned to Allah is he inferior to the born muslim who never committed kufr and how does one move on from that

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.

Whoever commits a sin such as Kufr or other sins, and then repents from it, then this does not necessitate that he will be in a status lower than the one who did not commit this sin.

Rather, by hard work, and striving hard in worship, submissiveness, and having a repentant heart, he may exceed the one who did not do this sin.

So, this sin will be a help for to be more obedient and hard working to the point that he precedes the one who did not do such a sin.

His is like a person who falls in a pit while walking; he might come out of this pit and continue his way to the extent that his hard effort in walking will help him precede those who did not fall in that pit at all.

The great rule in this is that Allah does not wrong a person an atom’s weight, as your Lord is not ever unjust to His servants. Allah Says (what means): {Indeed, Allah does not do injustice, [even] as much as an atom's weight; while if there is a good deed, He multiplies it and gives from Himself a great reward.} [Quran 4:40]

Allah knows best.