1) Those Democrat-led cities don't exist in a vacuum, if federal policy maintains existing poverty (and it does), changes at the local level will only ever be tinkering around the edges.
2) Then do more to make the countries from whence those immigrants come more appealing. I don't know, apply the opposite approach of yesteryear and support democratically elected leaders, whoever they are, and the process by which they get elected. Installing autocratic puppets might be good for US business in the short term but it's bad for the US (and thus US business) in the long term, QED.
3) It is the GOP that is responsible for lowering taxes on those that can afford it. Along with these cuts, they simultaneously pine for the halcyon days of the 50s (when the top tax rate was 90+%, BTW, and under a Republican president) in service to an economic fable that has repeatedly been shown to be false (and is provably false even in the context of the Reagan tax cuts that are so often used to support it). The GOP are responsible for upping spending on unnecessary frivolities like further increases in already excessive US military spending and the corporate socialism of giving billions to the (already wildly profitable) fossil fuel industry.
The GOP have done a very good job of making people think that these things are non-negotiable and can't even be talked about, whilst the actual necessities of human life are talked about as nice-to-have. That no longer holds water. In fact, it never did, that's why the GOP have to suppress voters and engage in gerrymandering (as well as benefiting from the Electoral College). If they went into a truly free and fair election they would consistently lose. Many of the things that the GOP have as negative planks (i.e. these are the things that we will never do) have 60+% approval among the general public.