One alternative to the Natures Head is the Separett toilet.
https://separett.shop/
If we end up doing a lot of boondocking, I'll probably go with a Separett or possibly a propane fired incinerator toilet.
FYI: One of the electric powerplants I use to manage had an (electric) incinerating toilet on the fuel oil unloading ship dock. That thing worked great. The electric power demand would be a bit rugged for a boondocking setup, though.