Nice playing. Welcome to the forum. Together, all of us will make the world hungry for the melodica. It may take 50 years however!
In terms of the key click, I actually like it most of the time as I am primarily a blues and R&B player.
I tend to play the melodica keyboard aggressively, having played rock and blues Hammond organ for many years. In my organ days, sometimes my hands would be bloody after a concert. The Hammond also has an electronic key click that is considered by many to be an essential part of the sound. So sometimes I play hard to get the click. But I am learning that to emulate the harp, I am better off playing legato.
I have been working very hard on my sound for the last couple of months and will post my latest advancements this weekend. It has been a struggle to get where I am. There were days when I thought I would just give up, but I am persevering.
In a few minutes I am going to post a recording that compares the sound of several melodicas. I promised I would do that.
Then I am going to make a recording of my latest efforts to get a cool “melodica blues sound.” Between unorthodox playing techniques and a few sound shaping tools that harp players use, the blues sound is starting to come together.