Praise be to Allah, and peace and blessings be upon the Messenger of Allah.
The answer differs according to what is intended by the phrase “the highest ideal.” If what is meant is: Who possesses the highest description and absolute perfection? Then the answer is Allah, Glorified and Exalted, alone. But if what is meant is: Who is the highest example to follow in methodology, conduct, and deeds? Then the Messenger of Allah ﷺ is the excellent example for believers.
If by “the highest description” what is meant is the highest description and absolute perfection, then this belongs exclusively to Allah. He is perfect in His Essence, Names, Attributes, and Actions, and there is none comparable, equal, or equivalent to Him.
This is the meaning intended in the two noble verses mentioned in the question.
Allah says:
“Say: He is Allah, One; Allah, the Self-Sufficient. He neither begets nor is born, nor is there to Him any equivalent.” [Al-Ikhlas: 1–4]
And He says:
“There is nothing like unto Him, and He is the All-Hearing, the All-Seeing.” [Ash-Shura: 11]
Thus, Allah has the highest description in every respect, meaning absolute perfection in which none of His creation shares.
If the question “Who is your highest ideal?” means: Who is your example in conduct, methodology, morals, deeds, striving, and patience? Then the meaning is different, and it is correct to say: The Messenger of Allah, Muhammad ﷺ.
He was the best of people in guidance, conduct, speech, and action, and Allah made him an excellent example for believers.
Allah says:
“Indeed, in the Messenger of Allah you have an excellent example for whoever has hope in Allah and the Last Day and remembers Allah often.” [Al-Ahzab: 21]
And Allah says in describing His Prophet ﷺ:
“And indeed, you are of a great moral character.” [Al-Qalam: 4]
When the Mother of the Believers, Aishah, may Allah be pleased with her, was asked about the character of the Prophet ﷺ, she said:
“His character was the Qur’an.”
This means that he ﷺ acted upon the commands of the Qur’an, avoided its prohibitions, embodied the noble qualities praised by the Qur’an, and avoided the qualities condemned by it.
Therefore, he ﷺ was the greatest example for believers in their worship, character, dealings, patience, striving, and all other aspects of life.
If “the highest description” means the highest description and absolute perfection, then it belongs to Allah alone. This is what is meant by His saying: “And to Allah belongs the highest description.”
But if what is meant is the example and role model in methodology, conduct, character, and deeds, then the Messenger of Allah ﷺ is the excellent example for believers.
And Allah knows best.