I tried the dmg but got the same error as before (getting the could not verify KMDeck was free of malware error). Privacy & Security was not giving me the option to open anyway. However the xatrtr command you provided did fix up the file and was able to open it. Again if I use the copy to Dropbox button and then in Finder move the files from my Dropbox to the Applications directory, it works perfectly fine without needed the xattr command.
Thanks for checking into this.