First, the Qur'an emphasizes in multiple verses that we as Muslims must obey the Prophet ﷺ, and to refrain from anything that the Prophet ﷺ has forbidden:
وَمَا آتَاكُمُ الرَّسُولُ فَخُذُوهُ وَمَا نَهَاكُمْ عَنْهُ فَانتَهُوا ۚ وَاتَّقُوا اللَّهَ ۖ إِنَّ اللَّهَ شَدِيدُ الْعِقَابِ
And whatever the Messenger has given you — take; and what he has forbidden you — refrain from. And fear Allah; indeed, Allah is severe in penalty.
— Surat Al-Hashr 59:7
In the tafsīr (exegesis) of the Qur'an by As-Saadi, he said that this verse covers all fundamentals and aspects of the religion: what the Prophet ﷺ ordains must be followed and one sins by not following his commands, and what the Prophet ﷺ forbids must be avoided and one sins by committing what he forbade. The reason for this is also in the Qur'an:
وَمَا يَنطِقُ عَنِ الْهَوَىٰ إِنْ هُوَ إِلَّا وَحْيٌ يُوحَىٰ
Nor does he speak from [his own] inclination. It is not but a revelation revealed.
— Surat An-Najm 53:3-4
The Prophet ﷺ does not ordain or forbid according to his own inclinations, but strictly according to what has been revealed to him. Not only so, but the Prophet ﷺ did not only accurately convey what was revealed to him without ommissions, but also did not add anything according to his own inclinations:
وَلَوْ تَقَوَّلَ عَلَيْنَا بَعْضَ الْأَقَاوِيلِ لَأَخَذْنَا مِنْهُ بِالْيَمِينِ ثُمَّ لَقَطَعْنَا مِنْهُ الْوَتِينَ
And if Muhammad had made up about Us some [false] sayings, We would have seized him by the right hand; then We would have cut from him the aorta.
— Surat Al-Haqqah 69:44-46
Second, the Qur'an does ask us to "beautify" ourselves but does not say anywhere that gold is the only element with which to beautify ourselves. We are free to "beautify" ourselves as men with anything other than gold or silk:
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ يَزِيدَ بْنِ أَبِي حَبِيبٍ، عَنْ أَبِي أَفْلَحَ الْهَمْدَانِيِّ، عَنِ ابْنِ زُرَيْرٍ، أَنَّهُ سَمِعَ عَلِيَّ بْنَ أَبِي طَالِبٍ، يَقُولُ إِنَّ نَبِيَّ اللَّهِ صلى الله عليه وسلم أَخَذَ حَرِيرًا فَجَعَلَهُ فِي يَمِينِهِ وَأَخَذَ ذَهَبًا فَجَعَلَهُ فِي شِمَالِهِ ثُمَّ قَالَ " إِنَّ هَذَيْنِ حَرَامٌ عَلَى ذُكُورِ أُمَّتِي " .
'Ali bin Abi Talib said:
"The Prophet of Allah [ﷺ] took hold of some silk in his right hand and some gold in his left, then he said: 'These two are forbidden for the males of my Ummah.'"
— Sunan an-Nasa'i, Book 48, Hadith 105
The fact that gold is forbidden for men in this world is not a matter of dispute among scholars. In the presence of a clear hadith forbidding gold for men, it follows that the restriction is absolutely valid:
وَفِي حَدِيثِ ابْنِ الْمُثَنَّى قَالَ سَمِعْتُ النَّضْرَ بْنَ أَنَسٍ، حَدَّثَنِي مُحَمَّدُ بْنُ سَهْلٍ التَّمِيمِيُّ، حَدَّثَنَا ابْنُ أَبِي مَرْيَمَ، أَخْبَرَنِي مُحَمَّدُ بْنُ جَعْفَرٍ، أَخْبَرَنِي إِبْرَاهِيمُ بْنُ عُقْبَةَ، عَنْ كُرَيْبٍ، مَوْلَى ابْنِ عَبَّاسٍ عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَأَى خَاتَمًا مِنْ ذَهَبٍ فِي يَدِ رَجُلٍ فَنَزَعَهُ فَطَرَحَهُ وَقَالَ " يَعْمِدُ أَحَدُكُمْ إِلَى جَمْرَةٍ مِنْ نَارٍ فَيَجْعَلُهَا فِي يَدِهِ " . فَقِيلَ لِلرَّجُلِ بَعْدَ مَا ذَهَبَ رَسُولُ اللَّهِ صلى الله عليه وسلم خُذْ خَاتَمَكَ انْتَفِعْ بِهِ . قَالَ لاَ وَاللَّهِ لاَ آخُذُهُ أَبَدًا وَقَدْ طَرَحَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم .
Abdullah ibn 'Abbas reported that Allah's Messenger (ﷺ) saw a person wearing a gold signet ring in his hand. He (the Holy Prophet) pulled it off and threw it away, saying: "One of you is wishing [for] live coal from Hell. and putting it on his hand. It was said to the person after Allah's Messenger (ﷺ) had left: 'Take your signet ring (of gold) and derive benefit out of it.' Whereupon he said: 'No, by Allah, I would never take it when Allah's Messenger (ﷺ) has thrown it away.'"
— Sahih Muslim, Book 37, Hadith 87
