Nowhere in the Qur’an or Sunnah or hadith you'll find that we should celebrate Mawlid.
The Sahaba who helped the Prophet ﷺ
spread the deen, also never celebrated Mawlid.
In books of Seerah, The scholars said that the date of birth of Prophet ﷺ is disputed. So, it's never 12th Rabi ul Awwal.
The Prophet ﷺ never celebrated Mawlid, nor Sahaba, nor Tabeen, nor Taba Tabeen, nor 4 imam but this invocation was done by the Fatimiyyah - the Shia.
Celebrating the birthday is the act of disbelievers.
The Messenger of Allah (ﷺ), said, “Whoever imitates a people is one of them.”