Is it obligatory to obey one's mother and abandon personal ambitions due to the heavy burden of helping her and receiving guests, or are there other solutions, especially since she is not convinced to reduce the number of guests?

Children must obey their parents in what they command, unless it involves disobedience to God or harm to the children, even if the parents are disobedient [to God]. Obedience to the mother regarding household chores and serving guests is obligatory, unless it results in harm, or causes one to miss a religious obligation, or a necessity for the children's livelihood. Obedience to parents is one of the best deeds and most rewarding in this world and the Hereafter.