Direct drive might make it power hungry, but a bigger negative is that tiny hyd reservoir will cause heating & foaming issues.
Pretty sure Hemi1966 bought his hyds for his grader from this guy, as does Premacon, Fumotec, THS and many others; lot's of different pump configurations to choose from to suit your flow & pressure needs.
https://www.modellhydraulik.com/
For an excavator you'll want as big of oil supply you can fit in your model to keep the oil warm to the touch at most. My Fumotec models use aviation fuel tanks & one particular model I made my own from brass sheet - soldered together. Some guys lately, like Cooper, are using clear acrylic glued together, so you can see clearly how full & clean your oil is.