Worshipping Guruvayoor Krishna is a powerful and fitting anchor for your Jupiter-Rahu dynamics. Regarding the snake connection, do not panic it does not mean you harmed or killed snakes in a past life. That is simply a classical structural feature of this placement, not a personal curse or reason to fear.
The deeper karmic theme of a Rahu-Jupiter combination relates to past-life ties with a Guru or spiritual authority, where knowledge or guidance may have been taken for granted or misused. Worshipping Krishna acts as a strong protective shield to balance this.
For simple, practical atonement (prāyaścitta), there is no need for complex or expensive rituals. If time permits, recite the Brihaspati Stotra every Thursday and offer simple daily prayers to Lord Shiva. This will clear the mental fog, balance Rahu’s chaotic energy, and keep your foundation grounded.