Link: https://www.europarl.europa.eu/petitions/en/show-petitions?keyWords=&years=2025&years=2024&_years=1&_searchThemes=1&statuses=AVAILABLE&_statuses=1&countries=EA&countries=EU&_countries=1&searchRequest=true&resSize=20&pageSize=20#res

Here is the link to submitted and published EU petitions and how to find them.
I find it interesting that the submitted petitions are processed directly by the European Parliament's Committee on Petitions.

The following link takes you to the search mask, which I filled in as follows in the thread title link:

https://www.europarl.europa.eu/petitions/en/home
=> Start search

• Year: 2024, 2025
• Topic: none selected
• Status: Open to supporters
• Country: All EU member states, European Union

Of course, you can enter whatever you want in the search box. (Multiple selections possible)
I don't quite understand why you would submit/search for an EU petition that only affects a single country. That is actually the responsibility of the country, not the EU. Perhaps someone has an example where an EU petition for a single country makes sense.