Is it ok to translate Qur'an with one’s own language without using any of the translations you listed, if one feels that he understands the verse though not up to the level of translators?

In order to translate a verse directly, one needs to have a strong grasp of the Arabic language, the rules of translation and the rules of Tafseer which apply to that verse. If these conditions are not met, there is a chance that the verse will be mistranslated or misunderstood.

My advice is that if you are translating a verse yourself, get a scholar or Arabic teacher to check it and make sure that your translation is accurate.

Dr. Yasir Qadhi lists the following conditions for a translation to be acceptable:

1) The translator must be a Muslim with correct Islaamic beliefs (aqeedah). This is because a person who does not believe in the Divine Authorship of the Qur'aan will never be able to do justice to its translation. This point was elaborated on in the previous chapter.

2) The translator must be proficient in Arabic and the language that he is translating in.

3) The translator must be knowledgeable of the grammar and peculiarities of the Arabic language, and specifically the Qur'an.

4) The translator must be familiar with the other Islamic sciences to a degree with which he can translate the Qur'an with the proper interpretation.

5) The translation must conform to the intent of the verse, such that it is a reasonable rendering of the meanings of the original. For this, the authentic, classical interpretations of the Qur'an must be consulted.

6) The translation must be complete, such that the original (i.e., the Qur'an) is not needed by the person reading the translation, or else the whole purpose of the translation is lost.

7) Neither the translator nor his audience may believe that the translation is the Qur'aan.[1]

If the above conditions are met, then there is no harm in translating it yourself.

Allah knows best.

Reference:

[1] An Introduction to the Sciences of the Quran, Dr. Yasir Qadhi, p. 350