@donquixotedelamancha wow
Wales was culturally and politically contiguous with England until really about 900AD. It rejoined in the 1200s and was completely unified with England in the 1500s.*
Lots of bits of the UK have their own traditions, that doesn't make them different cultures. If you go to Wales you will see that the people are very much the same as anywhere else.
All I can say is you've clearly visited and learnt about a very different Wales to the one I know, especially at the moment when many people are resenting the English coming in to self isolate in their second homes, putting pressure on already overstretched and overwhelmed resources.
The Welsh language has been under pressure since Tudor times when Henry VIII banned its use in court despite the Tudors relying heavily on the Welsh for their victory in the War of the Roses. The tudors are the reason for the white and green on the Welsh flag. Further pressure was added by the Victorians who saw the language as one of the many things holding the Welsh back.
More recent examples of the imbalance of power between Wales and England lie in the creation of many of the reservoirs that flooded fertile Welsh valleys to supply water to English cities. Cofiwch Dryweryn.
The idea that Wales rejoined in the 1200s is also an interesting take on Welsh history given all the castles built around it in order to subdue it.
Finally, Wales was not politically contiguous with England until 900AD. The word Welsh comes from an Anglo Saxon word meaning foreigners. They started invading from around the 6 century and pushed the natives back to areas including Wales and Cornwall. The 9th century AD King Alfred the Great the man who started to form England as we know it today never ruled Wales. Offa's dyke was built a century earlier as a border between Wales and the kingdom of Mercia.
Not only do Northern Ireland, Wales and Scotland have their own traditions, they all also have their own unique view of British history. After all there must be a reason why a Welsh man will automatically choose to support whatever team is playing against England when he watches his rugby.