The country filter hides Worldwide competitions. That is the whole cause. A competition with its location set to Worldwide is deliberately excluded the moment you tick a specific country, and Worldwide is by far the most common setting on UNI, so filtering to one country strips out most of the catalogue in one go.
Tick Worldwide as well
Worldwide sits at the top of the Location list, above the countries, and the list takes more than one choice. Tick Worldwide together with your country and you get both sets: everything set to Worldwide, plus everything set to a place in that country.
That combination is almost always what people mean when they filter by location, and it is the one to reach for first.
Why the two are kept apart
A competition's location is a single field. It is either a real place or it is Worldwide, never both, so the two cannot be matched by the same query. Asked for one country on its own, the filter returns competitions set in that country and removes the Worldwide ones rather than mixing them in.
Read the filter as "where is this competition set", not "where can I enter from".
Location is not an eligibility rule
This is the part worth being clear about. The Location filter tells you where a competition is anchored: the city its brief is about, the country of the institution running it, or Worldwide when it is not tied to a place at all. It is not a statement about who is allowed to enter.
A competition set in Italy is usually open to anyone. If a brief does restrict who may enter, that restriction is written in the brief itself, and the Location field is not where it is expressed. So filtering to your own country to find "competitions I am allowed to enter" gives you the wrong list twice over: it drops the Worldwide ones you can enter, and it keeps the local ones you may not qualify for.
Using the filter well
- Open the filters and select Location.
- Tick Worldwide first.
- Add the countries you care about on top of it.
- Apply. Your active choices show as chips above the results, and each chip can be cleared on its own.
If you are browsing rather than hunting for a place, leave Location alone entirely and filter by discipline instead. The full feed is more useful than a location-filtered one for most people.
If a country returns nothing at all
That is a real answer rather than a fault. Only a handful of competitions are anchored to any single country, and many countries have none at all. Add Worldwide and the list fills out.