Are we talking the Numark Mixdeck Express 3-channel with CD and USB? Not an entirely cheap unit and current, so not sure if this is what you mean.
Most controller will also work with VDJ, I believe it’s the software with the most supported controllers. So while you might not use your full Serato software (still a few that come with only the Intro version too btw), you can still use it with VDJ.
Not sure if that budget is 800 USD or EURO, but you should be able to shop for something nice in that category.
Pretty much you are saying you can live without the USB-stick and CD capabilities but want more FX control and perhaps performance pads?
You’d be looking at stuff like DDJ-SX and Reloop Terminal Mix 8, perhaps Denon MC4000 or 6000mk2 (the latter two have no/limited performance pads). If you switch to Serato, maybe the Numark NV.
Hope that helps.