Ramadan is not a reason not to travel to Oman during this period, but you should be aware that there are certain restrictions. The itinerary may need to be adjusted. If you like to sit in the sun a lot in street cafes, travelling during Ramadan makes little sense. Museums and public institutions sometimes have reduced opening hours (usually only in the morning). Eating and drinking in public during the day (until sunset) should be avoided. Many hotels do not offer alcohol.
Food shops are open and the supply in large malls is plentiful, so you can easily stock up for the day with dried fruit, date biscuits or whatever your heart desires. Whenever you are among yourselves, i.e. in a hotel room, in a car, in a lonely landscape, you can of course always have something to eat during the day. There are no morality police or anything like that, but respect is expected. Most hotels also offer extra dining rooms/restaurant areas for non-Muslims to eat in during the day or offer room service meals. Desert camps and most guesthouses also cater to non-Muslim guests.
According to Muslim customs, it is generally allowed to eat and drink in case of health problems, and children up to puberty age do not fast as a rule. Omanis are usually open-minded and tour guides in particular know very well that European tourists do not fast and understand that non-Muslims want to have something to eat in between. On guided day tours, it is best to openly discuss the topic at the beginning of the tour.
Life in the country is slowed down by Ramadan - in addition to the fact that the clocks in Arabia tick a little differently. Please treat the locals with indulgence as fasting is challenging in the heat and performance drops in the afternoon. Social life shifts to the evening hours, when people often eat extensively after sunset. Traffic often becomes hectic shortly before sunset, as everyone wants to be home in time to break their fast.
Ramadan also offers advantages and makes a trip during this time a special experience: Especially in the evening, the atmosphere in Ramadan is particularly beautiful when the locals meet at sunset to break their fast together. Even in front of small shops, the picnic blanket is spread out and dates and coffee are ready until the "starting signal" for the meal is given. The shops are sometimes closed for a short time for this ceremony. The mood in the country as a whole is literally "inspired" by this month dedicated to religion. The locals use the evening hours to go out. And: There are fewer tourists during Ramadan. For those who appreciate travelling in quieter times, a trip during Ramadan can be just the right thing.