It depends if you are doing it yourself or getting someone in. Beware, there is probably a membrane under the gravel so you won't be able to just dig.
Are you able to mow once a week? Is there anywhere to store a lawn mower?If it doesn't get heavy (kid) traffic then a shade tolerant grass mix should be OK and you don't have to keep it too short (especially if you agree that dandelions and daisies are, in fact, flowers, which they are
)
Shrubs will be easier to look after than flower beds, especially if you select the kind that never get too big and/or respond well to a once a year prune. If you are in a terrace you probably want to go for the former.
Alternatively you could pave the lot and use containers but that means getting compost in, watering more, etc so more hassle IMO
If nowhere for a lawnmower, then I would go for paving and either small beds in a creative sort of shape (but don't ask me!) for closely planted plant shrubs. ~They can send their roots under the paving, you just need to be able to get them planted. Mulch thickly between thhe shrubs (usually chipped bark but maybe you could re-purpose the gravel?).
You will eventually get a few weeds even with paying, but a lot fewer and you can ppour boiling water on them when they are tiny and that should keep things clear. But mind your toes.