I really hope to have merit even though it's only one, but why is it so hard for me to get it, even though I'm a member since 2016
Because you concentrate only on bounty campaign, that's why you had not received any merit still now. In order to earn merit you have to make constructive and useful topic. Otherwise you can't expect merit on your bounty reports. Bounty report isn't consider even as a good post. So try to improve your posting behaviour and try to contribute yourself.