"O mankind! It is you who stand in need of Allah ,but Allah is Rich (Free of all wants and needs), Worthy of All Praise." (Qur'an, 35:15)
Allah also makes it clear in the Quran that if everyone on the earth disbelieved it would not harm him one bit, similarly if everyone believed and worshipped him devoutly it would not increase him one bit, he is completely free of need.
The benefit in worshipping Him, is for the worshipper and not vice versa.
I think part of the confusion that many people today have is that they are not aware of what the exact nature of the relationship between God and man. Did Allah/God create us and just leave us be, or is it deeper than that?
well Allah in the quran says he is our Rab, typically this is translated to Lord, but it is deeper than that. This has to do with the richness of the arabic language compared to the english language
"In Arabic the word Rabb has three meanings: (i) Lord and Master; (ii) Sustainer, Provider, Supporter, Nourisher and Guardian, and (iii) Sovereign, Ruler, He Who controls and directs. God is the Rabb of the universe in all three meanings of the term."