I think for iOS samplers, a lot of people tend to recommend Koala but I don’t know if it can do secondary loop bracketing. I know it can loop with ADSR. You might also check out Samplr… that app seems really powerful too.
When it comes to the video you posted, and specifically hardware, the author of the video claims one (the Blackbox or the Digitakt) isn’t necessarily better than the other. However I have found the BB to be more flexible in general when it comes to tweaking, managing, and slicing samples… even if only for it’s ability to zoom into the waveform. The zooming is incredibly important to me because some of my recordings are a minute long, or longer, and grabbing little textures is a breeze on the Blackbox.