Any resources or information that could help me, as an autistic person, understand Irish Culture/Heritage?

Hi!
So, I'm in Wales but my grandma moved from Co. Sligo in the 1950s. She was born and bred Irish. I'm a trans guy, and the UK is becoming more and more unsafe for me by the week, so I've started researching the process for getting an Irish citizenship (it's not easy, especially if you're trans). Alongside this - for both related and unrelated reasons - I've recently become more interested in learning about cultures and colonialism, colonialism because I know the UK is oppressive, and cultures because I've never really been able to understand or connect to a "culture". I always felt like I was floating between them, if that makes sense?

I'm very, very wary of overstepping - I know many people with incredibly little Irish heritage often call themselves Irish and just misrepresent the culture, traditions and history, and being quite obviously autistic I really struggle to tell where that boundary is.
I've started by learning more about the history - in the UK we're taught nothing about the atrocities committed within and beyond our borders (with the exception of, and I quote from a project about the British Empire that I did at school, "people didn't like being part of the British empire because they wanted to control their own areas" - and holy shiiiiit it's disturbing what the UK has done globally, and how we don't teach the history even now colonialism is supposedly condemned. Like, I knew the UK was oppressive, especially with the empire, but recently I've realised how bad we were closer to home, such as in Wales and Ireland.
But, I digress, I'm also going to start looking at language resources, as I love celtic languages in general (Welsh Learner), and I want to learn more about this heritage that has been honestly suppressed and put down by the society I grew up in.

This is where my problem is - part of my autism is that researching really broad topics can really overwhelm me as I don't know where to start, and there's too many options, and I can't categorise things in my head. I want to learn more about Irish traditions, heritage, history, culture in general, and I want to learn more about catholicism despite being an Atheist so I can better understand people's beliefs - especially considering it seems to have been so important to my heritage. I'm also planning to go to both Dublin and Sligo as soon as I can work out how to plan an international trip.

Obviously, I wasn't born in Ireland, nor was I raised there, so I know I'm not fully Irish, but I want to understand my roots and feel like I have a community and a culture as being just a disabled mess growing up, I was so alone.
So, all of this being said, I have two main questions, does anyone have good resources regarding the things I want to learn about, or know anywhere I can find them?
The second one is a bit weird, but on forms here we have to fill out ethnicity, which as far as I understand is based on a mix of ancestry and culture, and they often allow you to tick more than one option. Is it wrong if I tick both White British and White Irish? I'm a quarter Irish, so when you can only pick one, I tick "White Mixed/Other" or "White British/Irish" when I can.
This genuinely stresses me out sometimes, as I feel like I have to give a "right" answer, and I feel like I'm sort of neglecting a part of me - but I also worry that I'm not considered Irish "enough"? Is there a boundary? I've just thought of it as I'm trying to connect to the culture more, and I'm eligible for citizenship, so it's okay, but I really want to know from people who have more of an idea from me, especially as I know people do use the label "Irish" when they're like 1/128th Irish lol. Sorry if I'm not explaining this well/this is rambling, I just want to understand myself and the world around me!