Some scholars of ahl-e-sunnah wal jam’ah say, "Fear Allah particularly in your isolation, He is everywhere"; while some scholars say that this type of statement is the ‘aqeedah of the Mu’tazillites. Which is the right opinion?

Allah's knowledge encompasses everything. He is the creator (Al Khaliq) above and beyond his creation (makhluq). Allah says several times in the Qur’an,

"thumma istawa alal ‘arsh",

"then He established Himself above the Throne"[1]

We don’t ask the how but just take it as Allah described himself. Saying Allah is everywhere is giving Allah an attribute he did not attribute himself with. This concept is in particular very dangerous if Allah would be everywhere this would mean that idol worship would become permissible as Allah is everywhere and anything would contain Allah. Also if Allah is everywhere he therefore must be inside me and you as well. There are many more authentic proofs from the Qur’an and Sunnah but to give another solid proof that our beloved Prophet (ﷺ) was called above the 7 heavens to receive the 5 daily prayers from Allah.

The belief that Allah is everywhere was not the belief of the early Muslims.

Reference:

[1] [Qur'an 7:54,10:3,13:2,25:59,32:4,57:4]