The battery is always the first place to look. Checking the charging system and the battery under load. It’s the most common starting point on a VE with the ECU dropping power hungry systems to keep other stuff going.
That’s why it’s always the answer you get. Once confirmed if an issue or not, then move to other areas of diagnosis.
Don’t get the sooks because that’s not what you want to hear. No one is psychic (in fact no human is until proven otherwise) and so won’t be customising an answer for you based on your beliefs in where a fault lay.
People have some unusual ways of “testing” the battery and charge system meaning they might not be doing it right and getting false results. Then spend time and money chasing the wrong thing.
We will continue to answer with, “check the battery” because that is the start.
Don’t be a tool.