Long time ago I use FPDF to create PDF Documents and reports. FPDF allows you to define a PDF using blocks. This process is slow as you can not reuse any of the views you already code in html or your frontend components.
For a long time there has been a new player wkhtmltopdf. wkhtmltopdf is a headless chrome port that generate PDF’s or Images from a website and you can use it in Symfony with Snappy bundle.