How many dmd is required for staking and how long for the coins to mature ?
there is no minimum value but to have a realistic chance to find regulary blocks u should aim for at least 200 DMD
200 DMD find on average a block every 10 days
100 DMD find on average a block every 20 days
50 DMD or less can take one or multiple months to find a block
all that average block find chance time mean active wallet in staking mode times
that means online and staking enabled 24/7