Will I be sinful if I continue trimming my eyebrow ends based on a fatwa from my country's mufti permitting the removal of eyebrow hair, in case the fatwa is incorrect?

The obligation of the lay follower is to ask trustworthy scholars. Whatever they rule for him, he acts upon it and is not sinful due to his lack of knowledge, for Allah Almighty says: "So ask the people of the message if you do not know." Scholars have differed on the ruling of trimming eyebrow hair (by plucking, shaving, or cutting). Some of them believe that the reason for the prohibition is resemblance to immoral women or deception, so it is permissible if it is not a distinctive mark of immoral women and no deception occurs. Some adhered to the apparent meaning of the hadith and made the prohibition specific to plucking and namṣ (plucking), while shaving and cutting are permissible. Some made the prohibition specific to women for whom adornment is not permissible, such as a woman in mourning (muḥiddah), while others see the prohibition as general for removing eyebrow hair by any means unless it becomes excessive. So, if you trim your eyebrow hair by cutting without plucking, imitating those scholars who have given you this ruling, there is no sin upon you.