Fwiw, I bought an 80 volt, 21” self propelled mower a few months ago- along with a matching string trimmer. Mower has 6 ah battery (that’s a lot of watt hours). Wet, tall grass, mulching uses a lot of power, but I got a bit over two miles of mowing before the battery showed empty (though mower didn’t stop).
I’m so over small gas engines, just bought a Sun Joe battery pole saw/ clipper/blower combo- they seem to have pretty reasonable stuff-
https://www.snowjoe.com/