As above, way too long for a trim router, Makita or otherwise.
Mortising you need a 1/2" router, and depending how deep you go, even that will scream making small passes once you get deep enough. Drill out the bulk of the mortise with a forstner or lip and spur bit first.
Just as an aside, 'cos I have the feeling the mortises may be for a workbench, and from one cheap sod to another
The legs on mine are made from cast off skids (those lumps of 3x3" or bigger that timber/builders yards use to drop pallets of sheet materials etc onto) the mortises are maybe 40mm deep at a push, plenty strong enough for my usage, though my set-up is 2 workbenches 900mm deep x 1200mm long which bolt together in any orientation depending on the job, or separately if need be
Edit: Forgot to add, the tops are 25mm Egger grey non-slip chipboard flooring glued together and lipped all around, with reclaimed 3x2" underneath to prevent any potential sagging.