Is it permissible to leave the current job, in which there is injustice due to non-compliance with the contract terms and theft of wages, and return to the previous job whose owner prevents the performance of Friday prayer?

We believe you should strive to demand your right and remove the injustice done to you so that you can remain in your current company, which does not prevent you from attending Friday prayers. If you are unable to do so, then there is no blame upon you for moving to another company, provided that it allows you to perform Friday prayers at their appointed time. If all of that becomes difficult, then it is permissible for you to work in this company until you find another suitable job that does not prevent you from attending Friday prayers.