It is recommended to be as specific as possible when choosing how to categorize your business on GMB. That said, it's not uncommon to find that there isn't a category available in Google My Business that perfectly matches your business. Knowing that the primary category you choose is the one that matters the most, you have to choose it carefully.
There are currently over 3,000 different options. If you are having trouble finding an adequate way to classify your business, it is recommended that you choose one that is broader than your current classification. For example, suppose you run a parcel shipping company. You won't find this category in GMB, but you will find "Shipping and Delivery Services", which is a little less specific, but relevant; so choose it.