5 or 6 tries.
One Nightmare of an Boss, i had so much struggle beating it (could have cleared it 1st trys but dont want to use the extra revive since i also dont know the patterns and just eat way too much damage).
For the most part even the first phase was hard since i even now am not able to read his attacks (yes he always goes up and down this ladder which anounce his next attack but i have never a clue which he is doing next), but i have learned that you can do that little side stutters to to avoid getting a full salve at once in your Vehicle. Or a even better strategy is to drive full speed always in shooting range from the left to the right. That way you avoid already some attacks without even knowing what comes and are faster to react based on the best way to dodge.
3rd way for the first part could be going on distance dodging the attacks and then smuggle some damage in between the attacks, but i think in the end that would be a bad strategy, and i dont try it so far.
For the Second Phase i have even less clue than from the first. I try to go on distance and just dodge everything, it is really hard even from distance and the boss seem to shoot forever in a neverending cycle i also dont see a pattern to dodge his bullets so my only way was to eat all his damage and outdamage him, sorry that i have not found a more satisfying way to beat him since against the hard boss or for lower geared Player there is no way i found to beat him with skill just luck and equipment. Just dont go so close in the second phase stay away in the outter shooting range that way you are not going to eat every damage, that prevented my clear in boss rush from the boss since i take a full load at the end which was half of my hp bar.