Answer: opinion regarding this type of people who call themselves Muslims, at a time when they are arguing for something other than what Allah has revealed, and they see Allah’s law as insufficient, and not valid for ruling in this age, is what Allah Almighty has said about them as Allah Almighty says:
فَلَا وَرَبِّكَ لَا يُؤْمِنُونَ حَتَّى يُحَكِّمُوكَ فِيمَا شَجَرَ بَيْنَهُمْ ثُمَّ لَا يَجِدُوا فِي أَنْفُسِهِمْ حَرَجًا مِمَّا قَضَيْتَ وَيُسَلِّمُوا تَسْلِيمًا [النساء:65]
But no, by your Lord, they will not [truly] believe until they make you, [O Muhammad], judge concerning that over which they dispute among themselves and then find within themselves no discomfort from what you have judged and submit in [full, willing] submission [An'nisa 65]
وَمَنْ لَمْ يَحْكُمْ بِمَا أَنْزَلَ اللَّهُ فَأُولَئِكَ هُمُ الْكَافِرُونَ [المائدة:44] وَمَنْ لَمْ يَحْكُمْ بِمَا أَنْزَلَ اللَّهُ فَأُولَئِكَ هُمُ الظَّالِمُونَ [المائدة:45] وَمَنْ لَمْ يَحْكُمْ بِمَا أَنْزَلَ اللَّهُ فَأُولَئِكَ هُمُ الْفَاسِقُونَ [المائدة:47]
And those who do not judge by what Allah has revealed are ˹truly˺ the disbelievers.(44)And whoever does not judge by what Allah has revealed - then it is those who are the wrongdoers [i.e., the unjust][45]And whoever does not judge by what Allah has revealed - then it is those who are the defiantly disobedient.[47].
So, those who refer for judgment to a law other than God’s law, and see that it is permissible for them, or that it is more appropriate than referring to the law of God, there is no doubt that they will get out of the circle of Islam by that, and by that they will be infidels, unjust, transgressors, as stated in the previous verses and others, and the saying of the Almighty and Majestic,
أَفَحُكْمَ الْجَاهِلِيَّةِ يَبْغُونَ وَمَنْ أَحْسَنُ مِنَ اللَّهِ حُكْمًا لِقَوْمٍ يُوقِنُونَ [المائدة:50]،
Then is it the judgement of [the time of] ignorance they desire? But who is better than Allah in judgement for a people who are certain [in faith].[50]