Initially when I starting selling stuff on exchange for bitcoin, I usually recieve the fund in my personal wallet then I'll have to send them to the exchange if I wanted to exchange them for fiat to meet some daily needs, just as you have complained I got losses due to fees but after finding out it's ok to recieve the funds on exchange and exchange then to whatever coins (for lower fees) or fiats for withdrawal, the profits got secured.

Currently all my crypto related service fees are been received on exchange although I don't keep them there for long, this has nothing to do with my personal funds that are bought just for holding for the future. These are funds that'll likely be used for trading or reinvested into other businesses that it's in the cryptocurency space. You can make use of exchange and weigh the difference too.