I had to order online cause I couldn’t find at any stores and it took a couple weeks to get in.
If you ask me, don't buy this. Buy a battery operated edger. I got a Ryobi and I got a 18 volt, 6 mAh battery. Works well and makes edging fast in less than 5 mins. This manual one used to take like 30 mins with a lot of effort and never gave me the professional look.
No . It is a single height
It could be that the little cutting blades that are on the outside of the wheels are now bent (they can be bent too easily) and are now blocking the rotation of the wheel. You can bend them back out again, but once you start bending back the metal blades, they become easier to bend once again if you hit a rough patch on the lawn edge.
The edger I purchased (May, 2020) has a rubber wheel assembly that is 4 inches in diameter and 3-3/4 inches wide. The metal blade is 6 inches in diameter. Therefore, the depth of the cut from the surface that the rubber wheels contact is 1 inch.
I would recommend this rotary edger.
They don't turn unless you physically push edger
I only use mine on lawn edges bordering on sidewalks and driveways. So I don't have any experience with it in your situation. But I don't see why it wouldn't work for your lawn bordered by a flower bed.
I don't think that the blades can be replaced; but at the low price for the unit coupled with the fact that the blades should last for years, you really don't need to sharpen them.
I don't believe that blades can be - or will need to be - sharpened.