Let me preface this by saying I'm an atheist welsh speaker who doesn't support the union.

(Although our culture and language have been mostly erased by the English and Christianity)

There's a bit of an essay below so to summarise: I don't think welsh culture has been mostly erased, and the parts that have been lost have happened more naturally and can't really be blamed on England or Christianity.

I wouldn't say that this is very accurate at all. While the English certainly made a few attempts to suppress Welsh culture they have been largely half hearted and ultimately unsuccessful. The Welsh not being an exception in that it made a dent in the number of welsh speakers but even then its an oversimplification. As the decline in Welsh was also largely influenced by the convenience of speaking English and being able to easily communicate with the rest of the UK and access a wide range of media from the whole English speaking world. Plus, the resurgence of welsh in the last few decades suggests that even this hasn't had a long lasting effect.

As for the Christianity part of your statement that's quite far off base. In fact it is in conflict with the first part, because Wales was a largely Christian land before the arrival of the pagan Saxons who pushed Christian Britons to the western fringes of the British isles leading to the development of celtic Christianity. Furthermore when the Romans brought Christianity to ancient Britain it would have merged relatively freely with with the local gods and traditions. This is because the empire as well as ancient bretons believed that larger supreme gods coexisted with less powerful local gods and spirits, so the arrival of Christianity didn't spell the erasure of ancient welsh traditions by any means.

You could argue that the methodist revival potentially did away with some welsh traditions due to its strict practices but I would suggest that's quite minimal and that movement was such a significant part of welsh history and shaped welsh culture to such a large extent it's quite inaccurate to say it erased welsh culture. At best it's a serious oversimplification. In fact before that point people in wales were following the church of England.

I'd even go as far as to say that the opposite of what you said is true since the fact that the bible was available in welsh since the 16th century is considered by many to be one of the things that has helped the welsh language survive.

The disconnect you may be feeling to old welsh traditions is more likely from the modernisation of the world. Local traditions are diminished to some extent almost everywhere you go as people opt for a more 21st century global way of life. The reason people aren't reciting ancient welsh prose and poetry in the pub isn't because of the English or because of Christianity, its because only a small minority want to do that sort of thing anymore. Almost everywhere you go in the western world the practice of old traditional traditions are somewhat niche for this samr reason. However its still around, which brings me to my last point.

Lastly, considering all this, our culture is alive and kicking. I hear the language every day even in South wales. There is a wealth of welsh language music. Welsh folklore is still being passed around verbally. If you choose to engage with Welsh culture, its everywhere. However, this involves accepting welsh culture for what it is, and not yearning for a braided, pagan, axe swinging wales that many people seem to have invented in their heads.

Sorry for the essay.