Almost every BJT transistor architecture construction diagrams shows a symmetric device. So, is there really any difference in operating a BJT transistor if you swap around emitter and collector? Indeed, there is, and it is due to the fact that these are always simplified diagrams. Generally, one of the two sides is more heavily doped and/or larger than the other. So this is what makes the transistor perform much better when operated one way than the other. However, it is still possible to operate the transistor with emitter and collector reversed, it’s just that you can only do so with a much smaller current. The particular niche application where you got better specifications on one parameter was all but replaced by modern MOSFETs instead.
20200809/https://en.wikipedia.org/wiki/Bipolar_transistor_biasing
20200809/DuckDuckGo what is the difference between emitter and collector
20200809/https://www.physicsforums.com/threads/difference-between-emitter-and-collector.800420/