I have done a crap ton of brush clearing with a cheap 4 stroke power head and one of these.

https://www.homedepot.com/p/RYOBI-Tri-Arc-Brush-Cutter-Blade-and-Expand-It-Brands-AC04105/100665186?cm_mmc=Shopping%7CG%7CBase%7CD28I%7C28-32_PORTABLE%7CNA%7CLIA%7CFixed%7c71700000041074954%7c58700004788398043%7c92700040946149284&gclid=Cj0KCQjw2efrBRD3ARIsAEnt0eiFFeTcU_GK06pOgxfCuT6vIlFnqJshYTEPRCwUSLkQbAfq9CrAx9YaAnOqEALw_wcB&gclsrc=aw.ds