Is it permissible to pray Dhuhr and Asr individually in the office due to an inability to go to the mosque, and is congregational prayer in the office acceptable, or is it obligatory to go to the mosque?

Congregational prayer is obligatory for men. Whoever abandons it while able to perform it, believing in its obligation, their prayer is valid but they incur sin. It is permissible to abstain from congregational prayer due to excuses, including fear for one's wealth or harm. If the workplace prevents going to the mosque and there is a fear of harm from non-compliance, then there is no sin in praying at the workplace, while striving to perform it in congregation. If that is prevented, then there is no sin in performing it individually. It is advised to seek employment that does not hinder the performance of religious duties.