Short answer: a divergence is when price makes a new high or low but the RSI does not. A higher high in price with a lower high in RSI is a bearish divergence; a lower low in price with a higher low in RSI is a bullish one. It says the move is losing strength — not that it is over.
Price pushes to a new high, but RSI peaks lower than it did on the last high. Fewer buyers are behind the push. It matters most at resistance and late in an uptrend.
Price drops to a new low, but RSI bottoms higher than last time. Selling is weakening. It matters most at support and after a long drop.
In a strong trend, divergences can stack up two or three times while price keeps going. Treat one as a reason to watch the next level closely, then wait for structure to confirm — a close under the last higher low after a bearish divergence, or over the last lower high after a bullish one. See market structure.
RSI above 70 only says the move is stretched. Strong trends stay overbought for days. A divergence compares two swings; an overbought reading is just one number.
When a Sylvo market read finds a divergence, it says so in the chart paragraph and draws the RSI under the chart.
The standard 14-period RSI works on every timeframe. Changing the setting rarely helps as much as reading it at the right place — at a level, against the trend's last swing.
Yes. Hidden divergence points with the trend: in an uptrend, a higher low in price with a lower low in RSI suggests the pullback is ending.
On its own, not very — it fails often in strong trends. Combined with a key level and a structure break, it becomes much more useful.