Is it obligatory to point one's toes towards the Qiblah while standing in prayer, or is it permissible to keep them slightly apart in a comfortable manner?

It is not obligatory to point the toes towards the Qibla perfectly, but it is recommended. Al-Bukhari narrated that the Prophet, peace and blessings be upon him, when he prostrated, would direct the tips of his toes towards the Qibla, and Al-Bukhari dedicated a chapter to this. It is better for the worshiper to point his toes towards the Qibla, and there is no harm if he spreads his legs in a V-shape, as long as he does not deviate from facing the Qibla.