I've found that the Bollinger Bands that I use for investing in the stock market, also do work well for Bitcoin on the weekly chart.
In addition to just regular dollar-cost-averaging (DCAing), you can also purchase BTCUSD aggressively when the RSI falls below 40 and/or price goes below the lower Bollinger Band.
I do not however recommend taking profit at the upper Bollinger Band. This is because when Bitcoin again goes on it's raging-bull / moon-run rampage, it will disrespect both the upper Bollinger Band, and the RSI.
This strategy is best used as a companion to regular DCA methodology.
Note: Disregard the strategy performance chart below, as the Bollinger Robot is not tuned to buying crypto - so there are insufficient orders for the performance chart to show.