sinc-M is always fixed length in number of taps, regardless of conversion ratio. sinc-Mx is always fixed length in time, regardless of conversion ratio. Meaning that sinc-M gets less steep as ratio is increased. While sinc-Mx keeps the same steepness regardless of conversion ratio.
sinc-MG(a) and sinc-L(l/m/s) work like sinc-Mx, that they scale depending on conversion ratio, so that the frequency response is always the same (meaning more taps are needed higher the conversion ratio).
What do you have as E-cores offload?
If you like above filters, using a powerful Nvidia GPU can make a huge difference.