The problem with Muslims is even more complicated than with the other ppl who don't know Christ. They actually know him very well, up to a point, he's part of Islam. But Islam functions on a very different value system so showing them the real Christ is almost impossible. For example in Islam persecuting Christians is almost a duty for every good Muslim.
Granted. But the question is: what do those who don't find the Saviour because he doesn't appear for them?
relax, (sort of). Yahweh is perfect, and perfectly just also, and perfectly merciful also.
believe it or not, Yahweh says in His Word what happens on judgment day for those who have not been
brought into His flock on earth. those who reject Yahshua, who reject Yahweh's Way, like roman rcc catholics who trust men instead of trusting Yahweh, are raised to shame and judgment.
if they trust Yahweh, and not men, then they are treated just like muslims who trust Yahweh,and not men -- Yahweh judges them according to His Perfect Wisdom and Justice ,
as it is written, those outside the ekklesia, Yahweh judges. (yes, also, it is written He has given all judgment to Yahshua. This is Perfect in His Way and Plan and Purpose and Knowledge. No discrepancy in Hiim.
so if you are wondering if Yahweh the Creator will be good and just or just plain evil towards the millions or billions who may never hear the truth of Yahshua Hamashiach,
you can relax in that regard and trust Him to Be Always Perfect in Mercy and Justice and Truth. This is as
it is written (you will perhaps have to find it eventually to know in perfect peace His Way). A lot of so-called believers
never find out..... they may or may not be judged themselves, it is entirely in Yahweh's Realm to do.