Well if you already start learning python then go with it, python programming has a lot of uses for example for data analysis , AI , web development and you can also create mobile application using python. since you have a background in cybersecurity i assume you already know how hackers use loop hole to hack into an application python is one of the most use language in ethical hacking. after you learn pythton go with java, java run in any platform as long as JRE is running and installed on that particular platform!
thats all i can help! by the way if there's any grammatical error please let me know , i want to be proficient in english language thanks! :-)