If you wanted to ignore any nuance and context regarding the verses of the Quran, you needn't have even gone this far to get a contradiction.
Just take the first verse you mentioned:
Do you not know that to Allah belongs the dominion of the heavens and the earth and [that] you have not besides Allah any protector or any helper? (2:107)
If you wished to ignore nuance, you could say that since my friend helped me in fifth grade by lending me a pencil and thus was a helper, this verse is false. This line of reasoning is, as you might realize, nonsense.
Nuance exists. Speech is not mathematical assertions, and it should not be analyzed that way. This verse does not prevent other people from being protectors or helpers but rather it states that only Allah is the ultimate protector and helper.
Meaning, when Allah decides something for or against you in this world or on Qiyamah, there will be no one to protect or help you against Allah. Other people being helpers or protectors in lesser capacities does not contradict that.
In lieu of your claims about this verse, you could say the same for these two verses:
Say, "O people, I am only to you a clear warner." (22:49)
Indeed, We have sent you, [O Muhammad], with the truth as a bringer of good tidings and a warner, and you will not be asked about the companions of Hellfire. (2:119)
In the first verse, it says Muhammad (SAW) is only a warner. In the second, Allah says he is also a bringer of good tidings. Which is it?
I hope you realize how nonsensical this question sounds. That is simply not how language works. When someone says, "I am only a [something]," he isn't denying his ability to be other things. He is simply making a statement in context to emphasize in the moment the [something] aspect of their being.
In the same way, when Allah says "There is no helper other than Me," He isn't denying the ability of other people to be helpers in smaller capacities. Instead, He is emphasizing that He is the ultimate helper. Language should be understood in the context and nuance it appears in.