Hey Cameron,
just in case you don’t buy some new bit, just a little improvement, assuming you use a 2-flute endmill, according to the formula linked above, I get 124 ipm (3.2 m/min.) with your 1/4" (6.35 mm) bit and 22.500 rpm for MDF material.
22.000 rpm would be “4” on the Makita (but as explained above motors like this do not reliably hold that speed).
However with a roughing bit you could increase feed rate.