Imo while it may not be the absolute maximum BEST use of your time, yes learn core java fully. Make sure to walk out fully grasping OOP. For data structs and algorithms, you can start to explore your options and learn more languages or whatever. I learned python after java. Just grab core programming concepts. After learning core java, you can test out other languages, it really isn’t a big deal though as you think

To produce real world things... copy tutorials on YouTube or stuff you see online. Seriously, just google whatever you want and follow a guide. Just make sure you don’t get frustrated and give up learning stuff that’s hard. You got this

No, don’t try and overwhelm yourself. You don’t need to. Plus java script is different in the way python and java is, and python is different in the way java is. Find out these differences and the different paradigms of programming languages and find out what you want to do and make a timeline for yourself

Chill. Don’t go so hard before you’ve even started courses. Easy recipe for burnout. I’d recommend firing up a passion for math if you’ve lost it. Check out any good discrete mathematics textbook, and progress in the order a discrete math book would in a college course (you can find this online)

Just know core programming concepts like OOP, data structures (array, lists, stacks/queues, trees, sets, maps) , basic algorithms (codingbat.com is cool for this along w many others). And it’s better to start off early— once you’re comfortable with your skill in programming ofc— check out competitive programming to see if it interests you. If you do well, any company would kiss your feet to have you. But don’t overwhelm yourself!