>didn't win a single battle
That's not true. Particularly in the first century or two, England would constantly "take" land then immediately lose it, and the borders of Ireland shifted constantly as the Gaels (or the assimilated Normans) would war with England or their vassals to seize land.

Most of the wars were not
>Ireland vs England
But instead
>England vs small petty kingdoms/tribes
So yeah, most of the time it wasn't really a contest. Still, from the initial invasion (1169) it took until the mid 17th Century to have actually conquered the island.

With that being said, the Irish did indeed manage to "catch up" and absolutely outperformed England by the end of the 16th Century, where Gaelic armies defeated English armies multiple times in field battles and brought the Lordship of Ireland to the brink of total collapse.

Is there a particular period or war you'd like to learn about? Happy to suggest books.