Talha ibn Abdullah said: A man came to the Messenger of Allah (peace and blessings of Allah be upon him) and when he drew close to him he asked him about Islam. The Messenger of Allah (peace and blessings of Allah be upon him) said: “Five prayers each day and night.” He said: “Do I have to do anything else?” He said: “No, not unless you do it voluntarily.” And the Messenger of Allah (peace and blessings of Allah be upon him) said: “And fasting Ramadan.” He said: “Do I have to do anything else?” He said: “No, not unless you do it voluntarily.” And the Messenger of Allah (peace and blessings of Allah be upon him) told him about zakah. He said: “Do I have to do anything else?” He said: “No, not unless you do it voluntarily.” The man left, saying, “By Allah, I will not do any more than this or any less.” The Messenger of Allah (peace and blessings of Allah be upon him) said: “He will succeed, if he is speaking the truth.” [Al-Bukhari (46) and Muslim (110)]
The scholars say that this hadith is to be understood as meaning that he did not offer naafil prayers and he did not omit any of the obligatory prayers. Such a person will undoubtedly be successful, even though his persisting in not offering Sunnah prayers is something blameworthy for which his testimony is to be rejected. But he is not sinning thereby, rather he will be successful and will attain salvation. And Allah knows best.
It should be noted that the naafil prayers bring immense reward and great virtue. It was narrated that Abu Hurayrah (may Allah be pleased with him) said:
“The first of his deeds for which a person will be brought to account on the Day of Resurrection will be his prayer. If it is sound then he will have succeeded but if it is not sound then he will be lost and doomed. If anything is lacking from his obligatory prayers, the Lord will say: ‘Look and see whether My slave has any voluntary (prayers),’ and the shortfall from his obligatory prayers will be made up from that. Then all his deeds will be dealt with in like manner.” [al-Tirmidhi, 413; Abu Dawood, 864; classed as saheeh by al-Albaani in Saheeh Abi Dawood.]
And the Prophet PBUH said:
“Whoever prays 12 rak’ahs each day and night, a house will be built for him in Paradise because of them.” [Muslim, 728]
12 rak'ahs mentioned in above hadith are: 2 Sunnah of Fajr, 4 Sunnah before Zuhr, 2 Sunnah After Zuhr, 2 Sunnah after Maghreb and 2 after Isha.
Why Am I mentioning it?
It is very important that we build our faith slowly and gradually add acts of worship to our daily routine without having any impact on the rights and obligations we have on others. Your first goal should be to make sure you complete obligatory prayers first. In case of prayers, it is 17 Fard rak'ahs only. If you can do that easily, then you can add the sunnahs I mentioned above. For many people from sub continent background, it is very easy because they are used to offer Sunnah with fard rakahs anyways.
Note: Witr is considered as confirmed Sunnah prayer which is read as last prayer one should pray for the night. Witr is not part of Isha prayer as many Muslims from sub-continent believe. For more details see link below:
https://islamqa.info/en/answers/3679...ng-witr-prayer
So far this is all good. Now I am not sure how old are you and what other obligations you have but I can tell if you start praying all voluntary prayers you asked about, there is very good chance that you will have less sleep. You will loose your focus to study or work or to do your day to day activities. If you are into memorization, it will affect your memorization. You may get into an accident due to lack of sleep. You may get frustrated due to lack of sleep and this may affect your relationship with others. You may start getting weight and this may lead to health issues.
I am not saying that you should not dream about doing all these prayers but I want to say is that don't take an extreme path. You may be able to do all this for few months and it is very possible that you quit praying all together after that. I have seen this happening quite a lot and that is why I am advising you to take a balanced approach. Do what's mandatory. Fulfill the rights your body, your family, your neighbors, friends, coworkers have on you. There are many doors to Jannah and we as a Muslim should focus on the middle path.
Anyways this is the advice I will give to my brother and you are my brother in Islam.
If Allah gave you an opportunity that you have plenty of time to offer the voluntary prayers then by all means go for it. Just be consistent.
Now to your main question (Ishraq and Duha Prayer):
There is a difference of opinion on whether the Ishraq prayer and the Duha prayer, termed “Chasht” in the sub-continent, are two distinct prayers or one and the same prayer. This difference of opinion is based on the varying hadiths which indicate the two possibilities, such as
“In the morning when the sun rises to the same height as it is at the time of Asr, the Prophet, peace and blessings be upon him, used to perform two cycles of prayer. When the sun rose in the east to the height where it is in the west at the time of Dhuhr, he performed four cycles of prayer.” [Tirmidhi]
Both prayers are prayed after sunrise. However,
the majority of jurists held that they (Duha and Ishraq) are one and the same prayer. They explain the apparent discrepancies in hadiths as referring to an “optimal” time to pray it, i.e. straight after sunrise (10-15 minutes after sun rise), and a “permissible” time to pray it, i.e. any time before noon. However, if one prays them separately as two distinct prayers this would be valid. And Allah knows best.
The minimum cycles of the prayer are 2, and the maximum cycles are 8 . Some hold the maximum to be 12, though 8 is preferable to all. Ideally, it is prayed in cycles of two.
See link below for more details:
https://islamqa.info/en/answers/2238...of-duha-prayer
https://islamqa.info/en/answers/1299...not-obligatory
Please make sure you always rely on Quran and Sunnah to take the guidance and not on the interpretation of someone (not me, not anyone else) who gives no evidence from hadith or Quran. I am not pointing this out to anyone, this is a general advice to all on this forum.