As hampshire writes: Stepping stones without a "foundation" are usually not a problem and most practicable for you. For planting, then low ground covers, depending on the region and light conditions, what grows well.
But unfortunately, you have to mow it regularly again.
I have a lawn mower robot that can't get there because of the garden gate,
and because of the 3 square meters, I don't want to take out a lawn mower and have it just standing around.
Of course, you can do that with stepping stones. Just take heavy ones that you bury. You can also embed an old wooden plank from the railway. It is drivable.
Of course it's possible – but you want something that looks like paving and are looking for options that are as low-maintenance and flat as paving. However, that is rather unlikely to work.