What is the optimal way to deal with money: saving it for marriage, or to avoid extravagance, or to perform Umrah, or for charity and sponsoring an orphan as was the original intention?

What you have mentioned is not a vow but a promise. You may dispose of your wealth as you deem fit. Spending on yourself is a form of charity, and whatever remains, you should donate to the closest relatives first. There is no harm in spending on yourself as long as it does not reach the point of extravagance. You are not obligated to save money for 'Umrah (definition). If you are in need of marriage, then hasten to acquire its means, as that is more prioritized.