We did a foster for a suspected pure Tosa Inu female once. She may or may not have been pure but she was previously used as a guard dog and after breaking through a window doing it's job she was given to a friends rescue.
I wish I had photos but I lost all of my pictures from that time period on a broken external drive.
Truthfully it's very unlikely to find a "real" or rather "ideal" tosa inu outside of Japan (at least by their standard).
She was a big girl, lanky, rather dry mouthed for a mastiff breed. She was guardy, DA, and loved to eat - a lot. She was a lot of dog to handle, physically and emotionally. I didn't have her a totally long time as one of the leads of the rescue adopted her as her own.
Supposedly most Tosa's here in America are somewhat bastardized versions of BYB mastiffs, I'm really not on the up and up on all of it. I have interacted with three other Tosas, two of which were imports from Japan (an adult and a puppy) and another that was, like your girl, a CL rehome. Honestly they all reminded me of my really tough, stubborn, "knows how big he is" great dane client. They were less accepting of strangers than Leo and less friendly with dogs but very similar, if that helps?