All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If you are directly involved in preparing pizza that contains pork, it is not permissible for you to do so, or to keep this job. But if you can keep your job without directly participating in preparing food that contains pork, then you are not sinful for keeping it. If it is proven to be prohibited for you to keep this job (i.e. if you directly partake in making such food), what you mentioned that you would fall in graver sins were you to quit the job does not justify keeping it. This is because it is incumbent on you to leave such an unlawful job, give up sins, and repent to Allah, The Almighty, of them. You should look for a permissible job and preoccupy yourself with what benefits you, such as seeking useful knowledge and performing good deeds. However, if it is permissible for you to retain your job (if you do not directly partake in making such food), yet you cannot perform the prayers, each on its due time because doing this incurs an evident difficulty upon you, then you are granted a concession, Allah willing, to combine the Thuhr and ‘Asr prayers during the time of either of them, and the Maghrib and ‘Ishaa' prayers during the time of either of them.
For more benefit on selling or delivering pizza which contains pork, please refer to Fataawa 85993, 82565 and 106975.
Allah Knows best.