When contemplating a new dive into the tractor world, or even the higher end lawn mower/garden tractor world, study the tractor and don't spend much, if any time on the hp rating. That is often merely a distraction.
Tractors, even the lawn/garden versions, tend to come in "series". Think of them as similar to a High School sports conference class or subcompact- compact- intermediate- full sized- luxury full sized sedans.
When you determine what class, what series best suites your needs, then finally, you choose which particular engine, within that series, with its hp rating you really need and are willing to pay for. Does that help?
It is not uncommon for vastly different sized tractors to share a similar engine size.