What should I do when urine splatters onto my clothes during urination and I cannot precisely identify the contaminated part, and it is difficult for me to change or wash my clothes at my workplace, which affects performing prayers on time or with the congregation?

If you are certain that your clothes have been splattered with urine, then you must wash the defiled part for prayer, because purification from impurity is a condition for the validity of prayer, and being at work or outside the home is not an excuse. However, if it is merely a doubt, do not pay attention to it. And your statement about washing up to mid-calf indicates that you are obsessive or do not perform urination properly, as urination does not usually result in clothes being defiled with impurity.