I dislike the "textbook" definitions of gender dysphoria I've seen so far. In my experience, these definitions are vague, inaccurate, or both.
I think they're misguided on a very basic level. Instead of simply and accurately stating what gender dysphoria is, they tend to rely on listing possible symptoms - such as the need to transition, thoughts of certain bodily features causing a feeling of wrongness, the need for a different genital configuration, etc.
The way I see it, there are two main problems. The first, as others have already said, is the manifestations and severity of dysphoria varies hugely from person to person. The second is that trying to define gender dysphoria in this way - giving it a set, concrete definition by pinpointing exactly what its manifestations look and feel like - not only results in an incomplete concept of gender dysphoria, but also hinders comprehensive understanding.
IMO, rather than looking at symptoms and manifestations of gender dysphoria, their source and causes should be examined.
Everyone has the need for their body to feel and be a certain way, and everyone needs to occupy certain social coordinates in order to be healthy and happy. This is why manifestations of gender dysphoria are so varied - everyone's different.
At the same time, it's also the reason why there are just as many commonalities as there are differences between people who experience gender dysphoria: for example, facial hair is a dysphoria trigger for many trans women, and breasts are a dysphoria trigger for many trans men. The details, perception, and manifestations may differ, but the underlying cause is that these features are in some way wrong for the person experiencing gender dysphoria.
(To address the OP:)
Yes, of course you can experience gender dysphoria and be active sexually. For some people who experience dysphoria, their genitals aren't part of it. Other people, their genitals might cause dysphoria, but they enjoy sex despite it. Others can't or don't want to do it at all.
