However there’s a passport card, which is nearly indistinguishable from an identity card:
The closest thing in Ireland was the "mandatory but not compulsory" Public Services Card and the related MyGovID, until it was ruled unlawful to require a PSC for access to government services.
There really is nothing like a mandatory national ID card in Ireland.
In practice things are more difficult without one one. (Mine expired in January. I didn't notice until I needed to pick up a package a few weeks ago. Ended up using my US passport instead.)
https://en.wikipedia.org/wiki/Identity_document says "A number of countries have voluntary identity card schemes. These include Austria, Belize, Finland, France (see France section), Hungary (however, all citizens of Hungary must have at least one of: valid passport, photo-based driving licence, or the National ID card), Iceland, Ireland, Norway, Saint Lucia, Sweden, Switzerland and the United States."
Checking Finland, https://en.wikipedia.org/wiki/Finnish_identity_card says it's about the same as Sweden: "Possession of an ID card or any ID document is non-compulsory in Finland, though interactions with officials and companies, like voting, picking up a parcel from Posti offices or buying alcohol when a salesperson suspects buyer to be under 18 or 30 years old, can be difficult or impossible without an ID card, a passport or a driving licence."
As I recall, in Sweden to vote without id you need someone who does have an id and knows you to vouch for you.
After all these years I still have no clue what is actually an official ruling of anything because I've had no problem showing my driver's licence when officially I'd needed my id card (in Germany). Then there's the decade old widespread rumour that you need to _carry_ any form of id, which is completely wrong (with a few exceptions).
Maybe in your EU country. ID cards are not mandatory in mine (Ireland) - a national ID card has been rejected by the electorate multiple times.
Be careful not to generalise your own experience to the entire bloc - it's not a homogeneous entity.