Use maxWidth with wordBreaks. i.e

const text = 'This is a really long bit of text and I want it to remain on the page and resize as needed and not get cut off';

pdfPage.drawText(text, {
  x: width / 2 - (text.length * 10),
  y: height - 200,
  size: 40,
  font: pdfFont,
  color: rgb(0.95, 0.1, 0.1),
  maxWidth: 500, wordBreaks: [" "]
});

You can do it using widthOfTextAtSize font property like this:

const pdfDoc = await PDFDocument.load(file) 
const pages = pdfDoc.getPages()
const font = await pdfDoc.embedFont(StandardFonts.TimesRoman)
const fontSize = 10

let centerText = setTextCenter(pages[0], font, fontSize)

centerText('This text is center aligned', xPos, yPos)

let rightText = setTextRight(pages[0], font, fontSize)

rightText('this text is right aligned', xPos, yPos)

const setTextCenter = (page, font, size) => {
    return (text, x, y) => {
        const widthText = font.widthOfTextAtSize(text, size)
        const props = {
            x: x - widthText / 2,
            y: y,
            size,
            font,
       }
       page.drawText(text, props)
    }
}

const setTextRight = (page, font, size) => {
    return (text, x, y) => {
        const widthText = font.widthOfTextAtSize(text, size)
        const props = {
            x: x - widthText,
            y: y,
            size,
            font,
       }
       page.drawText(text, props)
    }
}

Thanks Eric, correction is done.