What is the ruling on benefiting from the increase in pension and free university education for children, based on the percentage of "disability" (maʻlūliyyah) that I obtained, given the doubts about using connections (wāsiṭah) to obtain this percentage, and the resulting feeling of unease and pangs of conscience?

If it is merely a matter of doubt and whispering (waswasa), then the medical report is presumed to be sound, and the retirement pension is lawful (halal (definition)) for you, and the services provided by the state are permissible for you. You must repent from deception and falsification. However, if you know that the report does not conform to reality, then it is not permissible (halal) for you to benefit from what is given to you, and you must refer to the competent authority to amend the report.