You must read the Qur'an correctly. At least vowels and letters should be pronounced correctly, even if you are unable to learn the whole art of tajwid.

The Arabic language is such that very slight mistakes in pronouncing vowels while reading may drastically alter the meaning, sometimes totally distorting it. On some occasions, you may be saying things which could amount to Kufr.
An hour a day of sustained learning for a month or so should be enough for an educated adult to acquire the minimum essential rudimentary skills in this respect.

No one can be absolved of trying sincerely to learn to read the Qur'an correctly. But while you are learning, the fact that you cannot do so should not be a reason to forsake your reading.

A non-Arab may never master the art of correct reading. Or, you may have no opportunity to learn. The Prophet was aware of such difficulties when he told Jibra'il, 'I have been sent, Jibra'il, to a people who are unlettered, among whom are old women and old men, boys and girls, and men who have never read a book' (Tirmidhi). You should, therefore, remember his reassuring words in this respect, though do not make them an excuse to shun or slacken your efforts to learn.

One who is skilled in reading the Qur'an is with the noble, virtuous angels who bring down the revelation; one who falters while reading it and finds it hard to read correctly, will have a double reward (for reading and for exerting) (Bukhari, Muslim).