I noticed you are just returning a k RAW value. StochRSI to chart should consist of K and D values.

From my experience, what will cause different k and d values is based on several factors:

1. K lookback period
2. D lookback period
3. Moving Average method (SIMPLE, exponential, weighted, Wilder's, or Hull) for both calculating RSI and StochRSI for D Value calculation.

When you use .mean(), this is an indicator that the MA is SIMPLE for calculating the RSI. The Kraken chart might be using Wilder's MA like a majority of the brokerages do within the charting (typically it defaults to this.)

I noticed that you are not calculating D. As well, you are finding the k RAW value and stop calculating, where you are not applying a MA method to your K RAW value to smooth it. Given the current code, you are not storing k values for every minute interval which would not make it possible to smooth it using .rolling.