It's a real problem identifying as a Welsh person and having it as a first language, but whenever I have to state I'm from Wales I'll either get the response "Oh Wales in England so you are English?" or "Basically English then" it hurts every time. Let's not mention how useless Welsh is in the modern day as less than 20% of Wales actually speaks the language and is decreasing every year (don't tell my Welsh friends that), but my family is quite traditional in that sense and I'm still glad I know it. Though, would of probably preferred to have English as a 1st language as I still find myself making basic mistakes when writing in English.
Anyway, I'll pitch in on anything that I can help with.
Congratulations on sticking up for your country of birth. I think people lose so much when they turn against their origins. I hate Richard Branson, and many others for doing that, and I respect Donald Trump for standing up against the deep state to protect his birth right.
I can understand your pain over the Welsh language, we have the same problem with English. The internet seems to have created a hybrid subset that is becoming the world standard, and it is losing the subtlety and potential for humour that is part of the "mother tongue". I'm having to adjust to the fact that many people don't understand the difference between words like insure, ensure, and assure, and they just use the single word "insure" to replace them. There are many other examples like this.
The use of sites like grammarly and Google translate just make matters worse in my opinion.