The dual-sport version of this bike is regarded as probably the most dirt-worthy street-legal bike out there, so I am guessing the actual dirt bike version should be very good:
https://www.orionpowersports.com/ori...lly-assembled/
A close second as far as pure dirt bikes go is this bike:
https://www.orionpowersports.com/apo...embled-tested/
The irony of the Apollo is that it, too has a dual-sport version cousin, but it is NOT very dirt oriented.
I know there are a few full-size bikes from XMotos if you look around on online dealers like powersportsmax.com But the main players will be the two bikes above.