Is it permissible for a Muslim to make a vow to God to perform a specific act of obedience (such as giving charity) if a certain matter is achieved for him, and is it a condition that this act of obedience be great in proportion to the need?

A covenant with God is a vow (nadhr), and it is disliked due to the reported prohibitions against vowing and the fear of being unable to fulfill it, as it brings no good and repels no divine decree. The consequences of a vow can be dire if the one who made it does not fulfill what he covenanted with God, like someone who covenanted with God that if He granted him of His bounty, he would give in charity, but then becomes stingy with it, which results in hypocrisy in their hearts. Obedience to God and gratitude to Him are encouraged without the need for a vow.