DIY RC Lawnmower Build: Exploring Battery Options and Specs

RC Lawnmower Build

No, I'm not just building a 15" cinelifter. Just tossing around ideas for a diy rc lawnmower, instead of dropping 4k on one. Final product would probably end up costing a similar amount, but this way i get to learn stuff as well. I'm thinking this would either be running off of a 12v lead acid battery, along the lines of a car battery, or an 8s or 12s lithium pack. Probably looking at an 18" metal blade, and aiming for around 2500-3000 rpm. That gives a tip speed of ~140m/s, so no worries there. I could potentially go with 2 power systems, 8/12s for driving the blade and 12v for driving the wheels. I'm mainly just looking for potential parts recommendations here. Ideally I can run this using elrs, cause then I don't need a new radio, but I'm also aware that this is not exactly the intended use case for elrs. Also tossing up whether I go with a big powerful servo and rc car style setup for steering, or something more along the lines of a rack and pinion setup with a geared down brushless motor. Thanks for any input