Is it better for someone who has newly embraced Islam to pray the obligatory prayers in the mosque, and what is the evidence for that?

Prayer is the greatest practical pillar of Islam, and congregational prayer in the mosque is obligatory. This is the soundest opinion of the jurists, and it is supported by legal evidence from the Holy Quran, the Sunnah of the Prophet, and the consensus of the Companions.

From the Quran: 1. The Almighty's saying: ﴿And when you are among them and lead them in prayer, let a group of them stand with you and let them take their weapons. Then when they have prostrated, let them be behind you, and let another group who have not prayed come forward and pray with you﴾ [An-Nisa'/102]. This indicates its obligation in times of security, even more so. 2. And His saying: ﴿And establish prayer and give zakat and bow with those who bow﴾ [Al-Baqarah/43].

From the Sunnah: 1. On the authority of Abu Hurayrah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: "By Him in whose hand is my soul, I had intended to order firewood to be gathered, then I would order the prayer to be called, then I would order a man to lead the people in prayer, then I would go to men and burn their houses upon them." 2. On the authority of Abu Hurayrah, he said: A blind man came to the Prophet, peace and blessings be upon him, and said: "O Messenger of Allah, I have no one to lead me to the mosque." So he asked the Messenger of Allah, peace and blessings be upon him, to grant him a concession to pray in his house. He granted him the concession. When he turned to leave, he called him and said: "Do you hear the call to prayer?" He said: "Yes." He said: "Then respond."." And in another narration: "I find no concession for you." 3. On the authority of Abdullah bin Mas'ud, may Allah be pleased with him, he said: "Indeed, we saw that no one would stay behind from it except a hypocrite whose hypocrisy was well-known."

From the consensus of the Companions: Such as the saying of Ibn Mas'ud, may Allah be pleased with him: "Whoever hears the caller and does not respond without an excuse, then there is no prayer for him."