i see Koinly is applying tax calculation on per wallet basis in terms of days of maturity (i.e. it does not consider the same asset i have throughout different wallets)
for example i could have 100 units in wallet A already over 12 months period and 100 in Wallet B.
If i sell in Wallet B it considers it as a short term sale, is this correct? and is there an option for koinly to consider all my wallets when calculating?
That is not true. If you transfer assets between wallets, the date of acquisition is retained. So if you purchase asset x and keep it for over a year, then transfer it to another wallet, and sell it, this will be considered a long-term held asset.