EV Riding Mower Motor Sizing and Suggestions

A side project I have planned for myself is to build an EV riding mower off of an old mower chassis. I know this has been done many times before, but I'm looking for a little bit of feedback regarding the motor size/power rating I should be looking for. I recently came across an article discussing battery powered motors and how the power translates from electric motors to internal combustion motors. spoiler The article's writer seems to feel that most battery electric mowers are severely under-powered.

I know that a simple power translation is 1 kW = 1.34 hp, but is it as simple as that? It seems a lot of DIYers are building electric cars with the equivalent power I might need for an electric riding mower. Can that be right?

My goal is to rebuild a riding mower with a 42" to 46" deck, and traditionally, those come with engines ranging from mid-teens to over 20 hp. I want to hear people's thoughts on whether I'm really going to need a 10 to 15 kW motor for this type of build, and if so, what would be the best value for motors/controllers in that class? I'd really like to use an off-the-shelf motor/controller solution because I'd like this to conversion to be easily reproducible if possible.

Thanks!