You mentioned that you don't think the UK is working for anyone in it. Does this include England?
(Not intended as a "gotcha," I'm from elsewhere in the world and would genuinely like to learn more about the situation/your opinion.)
It absolutely does include England.
England doesn’t have its own Parliament because it’s all seen as being at ‘UK level’ so communities and constituencies get ignored.
England’s lack of decentralisation makes it harder for other parties to gain a foothold in any sort of local politics as everything is funnelled through the two party system of Tories vs Labour.
The UK breaking up wouldn’t be an end to cooperation between the countries here. At the moment the two parties can point fingers and blame the dastardly SNP or Plaid Cymru for agitating the balance of politics.
If the UK weren’t to exist, England would hopefully get to have a moment of self-reflection and decide what country it wants to be.