If you want to get stronger you will build some muscle. They kind of go together. CNS optimization (aka increasing muscle tension) and technique are also important, but getting stronger goes hand in hand with adding lean body tissue (muscle, tendon, bone).
The body adds lean body tissue as a biological adaptive response to being exposed to a stress. Muscle is added as a biological response to the stress of pressing. If you continue to press more and more weight, the body must respond. Technique and CNS adoptions will occur 1st, since they are less costly and easier to acquire, then muscle growth and even bone growth. Obviously, as you progress from being able to press, for 5 reps, the 16 to 24 to 32 to 48 kg Kbell, your body will change to accommodate this added stress. This change will include lean body tissue addition (muscle). The version of you that can press 48kg for 5 reps will have a different arm, different brain, different nervous system VERSUS the version of you that can only press 16kg for 5 reps.
Non-functional hypertrophy seems very unlikely. Because if you don't stress that muscle with excersise, it is unlikely that it will be forced to adapt. I think the phrase "use it or lose it" would be appropriate here. I'm not sure "non-functional muscle" exists. I would love it if you could show me an example.
A lot of Pavel's writing (especially earlier works) really focus on "strength being a skill". To focus on muscle tension and re-wiring the nervous system to use full body tension (vs isolation). It was revolutionary! But that doesn't mean that adding lean body tissue isn't important.
I'm familiar with Pavel's story about muscly men not being able to press an 88 lb (bulldog) KB at an expo (the Arnold, maybe?) If a muscly man struggles to do a press with an 88 lb KB, one must ask "why"? To me, I imagine that this muscular person's muscles are an adaption to stressors he experiences. Possibly even an adaption to muscular endurance (medium weight, high reps, or bodybuilding). These stressors may not be overhead KB presses. ~20 years ago, the KB was novel. Pressing an awkward object with a thick handle and uneven center of mass requires a bit of practice. No matter how strong or muscular somebody is, what % of these folks could press an 88 lb KB on their 1st attempt? I imagine not too many. I started with a 20kg bell, for example, and I had and have more strength and "muscle" than the average person with a background in strength training. But give that person a couple sessions of practice and I would bet he could press the 88 lb KB (40kg) before the less muscly trainee (all other things being equal).
For 99% of the population, fear of gaining too much muscle is likely mis-placed. There are exceptions though. For example, I could imagine that a serious rock climber would not want big, heavy, muscular legs to weigh him down
A rock climber training heavy squats probably doesn't make sense. Or maybe a serious ultra long distance endurance runner would want to keep their body weight in check. An extra 10 lb of muscle may slow them down. Or any sport that has a weight class. Those athletes must sacrifice certain adaptations in order to stay within a certain weight.
What are your goals?