Use left justification and default margins.
Readers with low vision who use magnification tend to use the left edge as a guide and not miss content. It also assists readers with neurodiverse medical conditions like dyslexia.
Justified text should be avoided. It creates uneven spaces between letters and words.
Be mindful of unnecessary space like empty paragraphs. A screen reading tool will attempt to read an empty paragraph. Use in-built paragraph and line spacing features to increase space between paragraphs.