Nothing short of an actual fight is fighting.
When you train, you are playing with thousands of tiny segments. Do not confuse the drills, nor your training, with the fight itself. You are preparing for a fight, but you never, ever actually fight as you train.
Sometimes, especially with longer drill sequences, we assume these are the movements in a fight. What you are actually doing is getting use to a host of tiny steps and tactile moments.
Often, we confront some portion of a drill. “I will never be able to pull this off if the guy is bigger than me.” If attempted in a fight in the same manner as the static, sterile, and compliant situation of the drill, you are correct. It will not work. In an actual fight, that particular situation will not arise as in the drill. You and your opponent will be moving in very different ways. Intent will be different. Everything will be different.
It is said most top military people like playing chess. They are not assuming the battle is like the game, yet the game prepares them for the battle. You are playing with drills in order to get tactics and to acquire general feeling. A particular drill move may feel uncomfortable, even useless. Fine, go with the flow. There are other concepts in the drill that will prove useful.
Sometimes, even within drills, rules or concepts seem violated. Perhaps a particular sequence, when played with a stronger partner, forces a moment of collapsed structure. Often, we will focus on that small moment, trying to reconcile it with a rule or concept. However, both drilling and fighting are fluid. A moment of partial collapse on the left may be the opening needed on your right. Look to the rules and concepts of your art, but do not consider them immutable at all times. If Van Gogh had not violated some rules, he would not have fought to give us a Starry Night.
Even sparring is not fighting. It is a step closer, but it is not an actual fight. Most of us understand the rules distinction. Fights have none. Moreover, your sparring partner does not really mean you harm. They may want to knock you out. They may even have some old grudge. However, they do not see you as an enemy to their survival.
It seems silly to say, but only a fight is a fight. Only a fight will have the energies of a fight and move the way a fight moves. Training consists of forms and drills. We play with these things, much like a painter mindlessly doodling in their spare time, all the while honing tiny concepts used when the work is at hand. Let the difficult or seemingly useless techniques roll off you. They are bridges to the thousands of useful moments around them.