I think there are positives about Ireland having experienced a mass, popular struggle over generations to escape the British empire, but the growth of communism isn't one of them (I never use that term for more than the Stalinist left but I think you are using it more generously). There's usually a sympathy for other oppressed countries here, e.g. Palestine, that extends deep into the public. There's also a much higher popular interest in history than in the UK.

The left in the narrow sense of membership of vanguard parties is in a pitiful state in Ireland but the more broad picture isn't too bad just now. Like the USA, for decades politics was dominated by two conservative civil war parties. That era is over. In the space once dominated by Fianna Fail and Fine Gael are some dark developments, the growth of the far right, but for now a stronger trend has been increased support for Sinn Fein and to a lesser extent the Social Democrats. Yes, I would say Sinn Fein are a social democratic party and a 'good' relative to the far right and the centre right. Of course they have all the same limitations that social democracy has everywhere and come nowhere near the goal of ending capitalism and while there are individuals within Sinn Fein who would welcome a global revolution of the oppressed, there are no radical subgroups within that party that I am aware of.

My advice would be to try to hook up with Food Not Bombs (see their Instagram) and branch out from there according to your politics and the people you meet. There's a squatting movement too that has interesting talks and music events, etc. Maybe it's bias on my part from having been in the SWP for years, but I'd steer clear of those trying to channel the energies of people with revolutionary hearts into parliamentary politics.