Ask HN: How Search a Mentor Online?

hi, i'll start a PhD in Machine Learning, after 3y in the industry as a backend eng. i know that my decision maybe was not a good idea, looking at the current market, but for the moment i don't have money problem and i got this opportunity , the problem is that i'm still a beginner in machine learning but i'm studying a lot. but i would like to find a mentor, or just someone to text outside my university. do you know if this is possibile ? or where can i find someone willing to guide me a little? thanks for your time.