How can the love of Prophet Muhammad, peace and blessings be upon him, be increased, while feeling the absurdity of existence and doubt in everything?

Allah created humans to worship Him, establish His command, and implement His law. Whoever complies with this deserves eternal bliss. Clear texts and sound intellects have affirmed this truth. As for the texts, Allah Almighty says: "And I did not create the jinn and mankind except to worship Me." As for the intellect, it realizes that humans did not create themselves, nor were they created in vain, for something that lacks a quality cannot bestow it. Rather, humans were created for trial and test in this world, and their duration is their life on Earth, after which they will receive their recompense. Allah Almighty says: "He who created death and life to test you – which of you is best in deed."