What is the ruling on softening the beard using chemical substances and hot hair straighteners?

It is forbidden to shave or shorten the beard, due to the command to let it grow. If softening the beard does not harm the skin, does not lead to its shortening, and is free from extravagance, then there is no harm in it. It should be known that excessive attention to hair, styling it, and oiling it is blameworthy, and the Prophet, peace and blessings be upon him, forbade much of "irfāh" (indulgence). Thus, excessive indulgence is blameworthy, while cleanliness and good appearance are مطلوب (desired) without extravagance. A man should not be preoccupied with styling his hair and beard and focusing on his appearance.