Which languages are the best ones to opt for if the final goal is full stack and perhaps a switch into the ML and AI world

I am looking for languages that serve as the best foundational languages I would need to step into full stack development, and use that base and experience to maybe switch to ML, AI, Data Science, maybe Fintech in the long run. I dont want to waste any time learning languages that would not help me in the long run.
Any additional tools I should start learning about and integrate in my daily usage that might add onto my skillset?