Hello and welcome!
I answered a similar question about learning coding in general with some ideas that I think will apply here too
Long story short: it doesn’t matter that much. You’ll have to pivot to a new language based on what your company uses, which is often based on what the developers already use and the kind of program you’re writing checks for.
Use any suitable example to learn the concepts behind coding and automation, then pivot to the new system.
Also the testing side of automation is important to understand. Automation is just tools used to help testing, so deciding on what to put into automation is important. An understanding of what automation is good at, what it can do, what adds to costs of writing and maintenance, what is worth repeating, what change does, what makes automation valuable and what makes it flaky and expensive. That’s powerful knowledge to take into a coding project.