Maybe I am just spoiled. My mower has 25 HP, cuts a 60" width, and goes a up to 6+ mph. It takes me several hours for a not very careful cut of my yard,
That mower cuts 0.4 m (16") width. 5000m^2 = a square yard 71m per side. Without overlap, it requires 177 passes. At 1 m/s (walking speed, about 2 mph), it would require 3.5 h (more with overlap). All that with a 10 Ah battery? It claims 1500 m^2 per charge, so 3 charges per 5000 m^2 (if charged to start).
That mower is not for me. Maybe for a small plot of grass, like a family plot in a cemetery.