Hotel breakfasts range from full buffets to a kettle and mini-fridge. You do not need a perfect nutrition plan on vacation. A useful goal is to build a breakfast that is satisfying enough for the morning without leaving you overly heavy before sightseeing.
At a buffet: build one balanced plate first
Start with a protein option such as eggs or yogurt, add fruit or vegetables, and include bread, oats or another carbohydrate. You can always go back if you are still hungry.
With a mini-fridge
Yogurt, fruit, cheese, milk and pre-made sandwiches can make an easy breakfast when you do not want a restaurant meal.
With only a kettle
Instant oats, tea, coffee and shelf-stable snacks can bridge the gap until you find a proper meal.
On hot sightseeing days
Include fluids and avoid starting the day already thirsty. If you are walking for hours in heat, a very heavy breakfast may feel uncomfortable.
Do not treat vacation breakfast like a test
Trying local foods can be part of travel. Aim for a pattern that leaves you comfortable rather than chasing exact macros.
Related: how to read a nutrition label.