Should I ground my body when working with 200V+?

Grounding won't protect you against shocks when touching live wires! Quite the opposite, the better you are grounded, the higher the resulting current through your body will be.

Grounding oneself, while working on live electrical equipment, would be an open invitation to disaster.

Insulating oneself from ground would be the only way to ensure total safety.

That's why rubber mats are provided on the door side of control panels. Electrical maintenance personnel are also provided with rubber shoes and rubber gloves and tools like pliers are also well insulated.

In spite of such protection the bigger danger is touching a live point with one hand and ground with the other. The best precaution against such an eventuality would be to always keep one hand in ones pocket while dealing with live equipment.

Such basic precautions should not be ignored even when use of GFCIs is mandatory.

You need to review basic electrical safety with your professor assuming you are in college. If in the workplace someone didn’t do a good job interviewing you and you need to ask for training. Electricity can kill you by causing your heart to stop and afib and it can literally cook you and cause your muscles to lock up as it is shocking you. You also need to know what to do if your buddy is getting shocked otherwise both of your could die vs only one. This is serious stuff. Anyone who works on electrical items even on their house must learn electrical safety

Edit: getting shocked at 220v is an incident that you must report in writing and is not your fault. Leadership needs to be aware so they can take the appropriate corrective action. This could be a problem with how you were instructed and the professor needs training on how to teach safety. You should have been tested and passed on safety before anyone let you on that project near high voltage. Your question confirms you were not tested on safety. If you are trying something out you saw on YouTube, please report it to YouTube so it can be removed. None of us here want you or anyone else hurt.