Revoke because I'm genuinely frightened of the consequences of leaving, long and short term. They seem far worse to me than riots and violence short term, though that would be terrible. I still think leaving even with a deal is worse. I think if the UK has any hope of recovery we need the support and funding of the EU.
As for how to fix it, I'd look to experts, of which I'm not one, but if you're looking for uninformed opinions/ideas:
Austerity clearly isn't working so that needs to be binned. Invest money into places where it will save money/reduce burden on other services/generate income. e.g.:
Fund the NHS properly and slowly bring it back so that the private contracts are phased out and it becomes an actual national health service again. That ensures best value for money. Currently, it's a private system which happens to be named the NHS, and it doesn't have the required capacity. Health problems including mental health problems exacerbated by this underprovision must be costing the economy, benefits system, and NHS itself a ridiculous amount of money.
Scrap/reform Universal Credit because it's barbaric and causing problems from mental health to feasibility of return to work to physical health to security of homes for children. All of which have knock on effects. First just go back to whatever we had before which was at least mostly functional. Long term consider the financial viability of a universal basic income system, or at least something extremely simple. Perhaps a three level system: Low-waged adult/Non-waged adult/Dependant top-up. (Second or more adult in a household classed as "dependant"). Forget about the notion of "scroungers", it is cheaper and more humane to support a few "scroungers" than it is to put so much energy into trying to catch people out especially when it penalises genuine claimants.
Put money back into education and family support, childcare, sure start centres, etc. Social care so that social services can handle caseloads adequately and elderly and vulnerable people bed blocking in hospitals can be moved to a more appropriate care facility and/or supported to return home. The dream would be community centres which replace the function churches once filled, there are a few dotted around already which do this well, so replicate the model - with the right mix of freedom to be run by local people plus funding these can do a massive amount of good and reduce burden on other services.
Look at other countries to see what they have in place in terms of state funded/subsidised/controlled - public transport, childcare, education, social housing/rent, libraries, sports, facilities, arts, business startups, etc - see if any of them are feasible to be implemented here and which are likely to make/save more than they cost.
Get young people involved in and clued up about politics and the EU - other EU countries have politics/civics as part of their school curriculum at least at the end of secondary school, and much stronger focus on languages.
And yes, of course, the first response will be "Where is the money for this?" Brexit has cost this country billions. If we can pull money out of our arses for that we can pull it out in order to make change that will actually benefit the country and encourage our economy to recover and blossom. Or make change incrementally, though I'd argue that the current state of the country is desperate enough to throw more rather than less money at it now. There is no point continuing with Brexit due to some ridiculous sunk-cost fallacy. Budgets of a country are nothing like household budgets and austerity is more about political ideology than saving money.