What if i only ever experience euphoria?

Euphoria isn't a permanent state. It is fleeting and temporary as real life doesn't work that way. So we then ask ourselves: how do I feel when I am not euphoric and I am entirely comfortable that way? If we are then great but if we are not then we may have some level of gender dysphoria.

If episodes of euphoria work for you then congratulations. Get rid of any lingering shame and guilt and live your life with the quantity of cross gender expression which fits within your current life framework and does not overly perturb it.

Conversely, if your baseline state (ie. outside a state of euphoria) leaves you with some lingering anxiety or depression or need to do more then there may be exploration required to find out why.