Rather than messing around with multiple process that get you nowhere, stick to one process and cure the problem!
Is the separation happening on all layers? If not, as I suspect is the answer, then what is the bottom of the first layer like? Is it smooth...or is it ridged, showing the individual extrusions.
If not smooth, then adjust the GlobalZ setting (on GCode tab) by a negative amount by minus 0.1mm and reprint. Check the finish again. If not smooth, repeat until the finish is smooth.
If the finish is smooth and you still get separation, try increasing the Outline overlap, slowing the perimeter print speed down, or even raising the temperature a tad. One or more of these has an effect on bonding around the perimeter. But NEVER adjust two settings at the same time unless you're 100% sure what you're doing! If one change had the desired effect, how will you know which one it was?