What is the ruling on praying Dhuhr and Asr while sitting at work in a Western country, knowing that going to the mosque takes a long time and it is not possible to pray standing at the workplace?

Fear of disgrace is not an excuse to abandon a pillar of prayer. The maximum harm that can occur is dismissal from work. If you cannot perform prayer properly at your workplace, then seek another job where you can. The command of Allah must be magnified and prioritized above all else, and there should be no leniency regarding the rulings of Sharia. What you have mentioned is not considered a valid fear that permits non-observance, as the majority of Muslims in those countries are able to perform prayer without harm. What is obligatory upon you is either to pray standing or to seek another job where you can do so.