The EU is an imperfect institution but it is not undemocratic.
Institutions must evolve to be responsive. Democratic nationalism (your system of choice) belongs to the 19th - 20th C.
It's hardly surprising that the politics of the nation state is not equipped to deal with some of the global challenges we now face.
Acknowledging this is not undemocratic.
The EU never set wage rates or work pension requirements and is not a panacea for all ills. Why do you think the EU should take responsibilty for Green and Ashley??
I do accept that since 2008 the EU has done a lot of harm dismantling collective bargaining institutions in countries like Greece, Spain, Portugal etc, but the bottom line is that we are not Greece, Spain or Portugal, and our collective bargaining coverage is so low since Thatcher that these EU actions have no practical relevance to the pay and conditions of UK workers.
My own view is that the next stage in our evolution will be a resurgence of fascism - and a degradation of employment terms and wages - not the democratic 'taking back of control' that many hoped for.
If the left were more effective and more trusted, things might be different - indeed we may have avoided brexit altogether - but they are not.