good stiffness is essential.
I bent the t-nut on my milling slide trying to get decent stiffness and had to cut a much beefier version which fits snug in the cross slide.
Any backlash on your cross slide will be obvious when you mill any kind of slot.
So it might take a while to sort out, but it’s well worth the effort.
An Axminster Micro lathe might struggle, depending on how ambitious the job is, some milling is better done under high torque high stiffness conditions, less heat.
Aluminium for example is a nightmare at high speed, and a doddle at low speed munching rates.