What is the ruling on combining two arduous jobs that lead to missing congregational prayers and circles of knowledge? And does the priority of seeking employment and self-development for marriage supersede the virtue of praying in the mosque?

There is no objection to the work mentioned, provided that it does not lead to neglecting religious duties, such as prayer in the mosque. Efforts should be made to convince the responsible party to allow performing prayers in the nearest mosque. If they do not permit that, then there is no dispensation for neglecting prayer, especially since the Prophet, peace and blessings be upon him, did not permit a blind man to neglect it. Furthermore, working sixteen hours a day may exhaust you and affect performing prayer with devotion. It is advised to fear Allah, for whoever fears Allah, He will make for him a way out and ease, and provide for him from where he does not expect.