I have tried all possible means to get my dad to accept the man I want to marry, but he keeps on saying no simply because of some cultural belief. The man I want to marry is a Muslim and religious, but from the look of things none of my family member is ready to stand as my wali. So what should I do?
I would say, try hard to convince your dad.
Show him the quality of this man, his characteristics, The voluntary work that he does, is he Hafiz for example, how he always takes care of his parents, and etc.
Try also to convince your mom, and ask her to convince dad.
If nothing helped, I would say, obey them. If you obey your parents, Allah will get you something even better InshaAllah.