Some Church Fathers did not believe in an eternal Hell and instead believed in the apokatastasis. You can read about it here:
en.wikipedia.org/wiki/Apokatastasis#in_Christianity
Origen, Clement of Alexandria, St Gregory of Nyssa, St Ambrose of Milan, and St Gregory of Naziansus all believed in the apokatastasis. St Jerome initially believed in it but then later changed his mind. According to Basil the Great who opposed the doctrine, the majority of Christians believed so. St Jerome also mentions this:
“I know that most persons understand by the story of Nineveh and its king, the ultimate forgiveness of the devil and all rational creatures.”
Apology Against Rufinus: Addressed to Pammachius and Marcella from Bethlehem, Book I, Chapter 27
The word “eternal” in for example the Gospel of Matthew you cite can mean pertaining to an age as opposed to forever and ever. So the Greek is unclear. What is clear is that God IS love. He is not merely loving as though love were just one of many of his attributes; he is Love Itself:
You can see on the Vatican website, it affirms that God is love itself. For example:
“Only love enables us to recognize the God who is love itself”
vatican.va/news_services/liturgy/2005/via_crucis/en/station_06.html