In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

Imaam As-Sadi [may Allaah have mercy upon him] stated in Ar-Risaalah Al-Lateefah:

“The Asl (fundamental principle or initial ruling) regarding commands in the Book (i.e. the Qur’aan) and the Sunnah is that they (necessitate) Wujoob (i.e. obligation), unless if an evidence to (show) that it is Al-Istihbaab (i.e. a recommendation) or Al-Ibaaha (i.e. a permissible). And the Asl (fundamental principle or initial ruling) regarding prohibitions is that they (necessitate) Tahreem (i.e. forbidden), unless if an evidence show that it is Al-Karaahah (i.e. disliked)”. [end of quote]

Imaam Muhammad Ibn Saalih Al-Uthaymeen [may Allaah have mercy upon him] was asked: Virtuous Shaikh, he (i.e. the question) has one last question, and he says: “How do we make a judgement on the Prophet’s [peace and blessings of Allaah be upon him] prohibitions as to whether they are [نواهي تحريم – prohibitions that necessitates that something is forbidden] or [نواهي كراهية – prohibitions that necessitate that something is disliked]?

Answer: This is also a matter of differing among the Usooliyyeen as to whether a prohibition necessitates that something is forbidden or disliked; some of them see that it necessitates something forbidden and some of them see that it necessitates something disliked, and some of them elaborated on the affair saying that if the prohibition is related to acts of worship, then it takes the ruling of something forbidden, and if the prohibition is related to ettiquettes, then it takes the ruling of something disliked. In reality (or in fact), there is no comprehensive rule for every prohibition that is reported from the Prophet [may peace and blessings of Allaah be upon him and his family], because indeed you come across prohibitions on which the scholars pass the judgement of Karaahah (i.e. disliked) and other prohibitions on which the scholars pass the judgement of Tahreem (i.e. forbidden). So, based on this, a person examines every prohibition specifically (in and of itself) as to whether it necessitates Tahreem or Kiraahah according to the Shariah principles. (see footnote a)

In summary, the answer is that we say: the scholars – in the affair of the prohibitions- have three statements: The first statement is that a prohibition takes the ruling of Tahreem absolutely; and based on this, whoever diverts a prohibition from being other than a prohibition is asked for evidence. The second statement is that a prohibition takes the ruling of Kiraahah absolutely, and based on this, whoever directs a prohibition to the ruling of Tahreem is asked for evidence. The third statement; the detail explanation is that if the prohibition is related to etiquettes and manners, then it takes the ruling of Kiraahah; and if related to acts of worship, then it takes the ruling of Tahreem (after examined specifically based on the Shariah principles). (1)

Footnote a: The Prohibition of Al-Qaza’ ― A Type of Hairstyle Disallowed by Allah’s Messenger Where a Part of the Head is Shaved and Other Parts are Left Long… Imitating the Styles and Fashions of the Unbelievers: https://abukhadeejah.com/the-prohibition-of-qaza-hairstyle-disallowed-by-allahs-messenger/

Ref 1:    https://binothaimeen.net/content/10830#:~:text=%D8%A7%D9%84%D8%B4%D9%8A%D8%AE%3A%20%D9%87%D8%B0%D8%A7%20%D8%A3%D9%8A%D8%B6%D8%A7%D9%8B%D9%8B%20%D9%85%D9%88%D8%B6%D8%B9%20%D8%AE%D9%84%D8%A7%D9%81,%D8%A7%D9%84%D9%84%D9%87%20%D8%B9%D9%84%D9%8A%D9%87%20%D9%88%D8%B9%D9%84%D9%89%20%D8%A2%D9%84%D9%87%20%D9%88%D8%B3%D9%84%D9%85%D8%9B paraphrased