EasyACC Slim TPU Case ($6)
Sometimes cases are too thick, which is why "slim" cases are a popular variant. These offer the thinnest design and possible while still offering enough bulk to keep the phone somewhat safe from drops or life's daily hazards.
EasyACC is a brand we've used on several devices in the past, and they have a new Matte Black soft and flexible TPU case for the OnePlus 7 Pro that looks like a great option for those on a budget.
You'll get oversized tactile buttons and cutouts for the mute slider switch and that pop-up front-facing camera.