I don't want to mow the lawn. I see this as a large waste of time, as well as a source of waste in buying a lawnmower, fertilizer, gas, oil, and having a negative effect on the environment.
I don't agree entirely.
It's true mowing the lawn requires time, but by mowing less often you can reduce the time needed.
However, you don't necessarily need fertilizer. If you use a mulching lawnmower, it will leave all nutrients on the lawn without moving any of them away. So, it's a closed cycle, no new nutrients necessarily needed.
As for minimizing time needed and the environmental impact of lawnmower, my solution is a gasoline powered lawnmower.
Surprised? I carefully analyzed this and considered the best solution after using a battery lawnmower mistakenly for 4 years.
For the first 2 years, the battery powered lawnmower worked fine. Then one battery of its 2 failed (it requires 2 to operate). I had to purchase 2 new batteries (no individual batteries were available for sale at the time where I bought the 2 new batteries). It was a wise purchase to buy 2 new, since a short time after, the second battery failed. The new batteries immediately often overheated, needing me to stop mowing since overheating protection would cut power, and start after hour of cooling down. A major annoyance. I used the repeatedly-overheating batteries for 2 more years and suffered the interruptions needed. Then the batteries had degraded to the point where they don't have enough capacity to mow my entire lawn.
My gasoline powered new lawnmower on the other hand is very ideal. In contrast to a battery powered lawnmower where you can't be certain whether compatible batteries are available for sale 10 years from now, the gasoline powered lawnmower takes gasoline, something that has been available for 100 years and will be for hundreds of years more to come. It consumes about 0.15 liters per mowing (so I can mow the lawn at least 5 maybe even 6 times with the 0.9 liter tank), or about a liter per year if I mow often, once every 2 weeks. So the environmental impact is around 3 kilograms of CO2 per year. Cost 3 euros per year.
Compare that to the environmental impact of having to buy two new batteries every 2 years, or a battery per year at 50 EUR / battery. I'm not sure about the CO2 footprint but somewhere I found out that for electronics manufactured in China, one euro spent in electronics is about as bad as one euro spent in gasoline at Finnish heavily taxed gasoline prices. So, I'd say the environmental impact of having to buy new batteries all the time is 10x the impact of gasoline. Futhermore, your expensive lawnmower could become useless due to manufacturer discontinuing compatible batteries -- perhaps the manufacturer went out of business, perhaps the manufacturer replaced its models with "new improved" models that use different batteries. With gasoline lawnmowers, all you need is maybe few spare air filters and spark plugs and it'll run forever.
The lawnmower also requires 0.5 liters of oil per oil change. At oil change every 2 years, that's 0.25 liters per year. It's true this has some environmental impact, but probably not as big as buying one 50 EUR battery every year.
If I mow the lawn 4 hours per year, the lawnmower lasts for at least 25 years until the service schedule reaches the point where the engine should be inspected by a specialist dealer (100 hour usage). It lasts for 12 and half years until engine oil needs to be changed by 50 operating hours (but changing by time every 2 years is advisable) and until spark plugs needs to be inspected (not necessarily changed). It requires cleaning the air filter by tapping it every 6 years (every 25 hours), maybe sometimes tapping isn't enough and a new filter is needed.
About the only mistake you can do with a gasoline powered lawnmower is by not using alkylate gasoline / small engine gasoline. Then the carburetor can clog, requiring expensive carburetor cleaning. By only using alkylate gasoline / small engine gasoline, it will not clog even if stored full of gas over winter.
By using a mulching lawnmower, the environmental impact is small. Don't mow it every week, let it occasionally grow flowers for pollinators. Also you can select an area you mow less often to allow even more flower growth.
A goat is way worse than a lawnmower. Goat emits huge amounts of methane, a significant greenhouse gas. Same is true of sheep and cows -- in fact, probably every animal that can eat grass. (Edit: found from https://www.tandfonline.com/doi/pdf/10.3402/tellusb.v38i3-4.15135 that a single goat produces 5 kg of methane per year; that's 150 kg of CO2 equivalent per year if we assume climate change happens slowly in 100 years, or 425 kg of CO2 equivalent per year if we assume climate change happens quickly in 20 years -- quite high to compared to 3 kg of year from lawnmower).
Robotic lawnmower could minimize time needed, but never let any flowers grow, since they mow so often, thus causing harm to pollinators.