It is not impossible to ride a gravel bike over a number of barriers given one paramount condition: practice. The first step is to find a small log or any such object that can be used to practice the lifting of a front wheel and then the back wheel alternately over it. Once you feel more confident, go for broader objects. This entails doing a tiny wheelie and raising your feet to elevate the back wheel over the object. With time, you will get used to riding over most obstacles on the bike rather than getting off it to cross the obstruction.