Wow! So much talking past each other -- all convinced of their correctness, but in various grades ignorant of the rest of the picture. Like the whole Touching The Elephant -- all convinced that they've got the right story.....
FWIW, I like much of what Chan and Davey have put together. But even they speak in absolutes -- and I'm convinced that they're both smart enough to qualify their various statements were you to corner them at a holiday party...
• Finding a decision rule with positive expectancy is a nearly trivial operation.
• Finding a decision rule with positive expectancy on daily data that goes back 20+ years is (IMO) foolhardy.
• Finding a decision rule with positive expectancy on daily data that may be tweaked every 6-9-12 months to continue that positive outcome set is an operation that *may* benefit from pattern-recognition routines that inhabit the machine-learning space, but ...
• machine learning depends on data stability that is at odds with the very nature of time-series phenomena, and
• developing a meta-algo to modify a floor-level algo is *also* a nearly-trivial maneuver -- just google "time-series decomposition" for examples that go back half a century.
In my tick-scalping days, I put T/A up that looked good for 20-30 minutes; I relied on it for the next minute or two. For trend-exploitation, I put up daily candles that go back maybe 6-12 months, and rely upon it for the next week or so.
HINT.