Is it permissible to dedicate oneself to seeking knowledge in Egypt, while leaving one's job in the UAE, knowing that the financial situation in Egypt might not be as good as in the UAE, and that the questioner supports a family of seven?

Seeking knowledge is among the best acts of worship. It is honor enough that Allah commanded His Prophet to seek more of it. If you can combine seeking knowledge with work, that is better. If you cannot and you have sufficient means, there is no objection to leaving work to devote yourself to knowledge. It is advisable to perform Istikhara (prayer for guidance) and seek counsel before making a decision.