I pray regularly fives, give sadakas (voluntary charity) and do other ibadats (rituals). I have a very weak point that I sometimes fail to control my anger. Most of the time I have a very hot temper. I sometimes misbehave and even use bad words towards other people. Afterwards I repent, but I repeat this bad behavior later. Is there 'doa' or sunnah to manage my anger.
There are ahadith which describe the importance of controlling anger:
Abu Huraira reported: I heard Allah's Messenger (ﷺ) as saying: One is not strong because of one's wrestling skillfully. They said: Allah's Messenger, then who is strong? He said: He who controls his anger when he is in a fit of rage. -- Sahih Muslim 2609 b (sunnah.com; also Al-Adab Al-Mufrad 1317 sunnah.com)
It was narrated from Sahl bin Mu’adh bin Anas, from his father, that the Messenger of Allah (ﷺ) said: “Whoever restrains his anger when he is able to implement it, Allah will call him before all of creation on the Day of Resurrection, and will give him his choice of any houri that he wants.” -- Sunan Ibn Majah [grade: hasan] (sunnah.com)
And also "The Prophet (ﷺ) said, 'Do not become angry and furious.'" Sahih al-Bukhari 6116 (sunnah.com), which IslamWeb interpreted as meaning "the cure for anger is to avoid its causes and stimulants".
From a psychology point of view, it can be helpful to identify the causes of your anger (e.g. anger out of frustration, i.e., when there are obstacles to achieving a goal). Cognitive behavioural therapy encourages one to be aware of their thought processes, and why certain feelings are being felt. This enables you to react more appropriately to situations.
So Islam espouses controlling one's anger. In fact, there are ahadith addressing how to behave when angry:
Narrated AbuDharr: The Messenger of Allah (ﷺ) said to us: When one of you becomes angry while standing, he should sit down. If the anger leaves him, well and good; otherwise he should lie down. -- Sunan Abi Dawud 4782 [grade: sahih] (sunnah.com)
The Messenger of Allaah (peace and blessings of Allaah be upon him) said: "If any of you becomes angry, let him keep silent." (Reported by Imaam Ahmad, al-Musnad, 1/329; see also Saheeh al-Jaami’, 693, 4027). -- sourced from Islam Q&A
IslamWeb also suggests performing ablution when angry, citing the following hadith (which is listed as "da'if" [weak] at sunnah.com):
Anger comes from the devil, the devil was created of fire, and fire is extinguished only with water; so when one of you becomes angry, he should perform ablution. -- Sunan Abi Dawud 4784 [grade: da'if] (sunnah.com)
Islam Q&A also includes other methods, e.g., listening to reminders: "sincere people will remember Allaah when they are reminded, and they will not overstep the mark" and being aware of the negative impacts of anger.