What makes a ladder really useful are individually adjustable legs. I’ve had adjustable legs on my ladders for 30 years. You can bolt them almost any ladder. (Ours is a 12-footer straight convertible into a 6 ft stepladder.) They let you level the bottom end of the ladder on uneven ground. Mine will handle 18 inches of difference.
There are several brands, many of which will only fit certain ladders. Most of those only accommodate three inches of difference, which is not enough. Also, the levelers you want are like this kind from McMasters, which are infinitely adjustable; most accessory levelers I’ve seen have a selection of set incremental positions that are, of course, not quite right most of the time.
Mine make their variable adjustment by means of a stack of tightly-fitting washers on the extension tubes. A spring holds them free when you squeeze the stack. Let go and the washers jam tight permitting no slack at all. They are very easy to adjust without tools. I think that there must have been a problem with liability lawsuits, otherwise the things would be in every hardware store. But even a ninny couldn’t mess them up. A guard protects the washers stack. They’ve never slipped or failed me in any way for 36 years.
The kind here costs less in real money than mine did in 1970 when I paid $20. I literally use mine every time we use the ladder here, at the chicken farm. They can also give you another 15″ or anything in between when leaning the ladder on something. You’ll love ‘em.