Need to Switch

Hu everyone.I have total 4 YOE. I am currently in TCS working as a Java developer. but currently I am feeling undervalued as i had to keep changing projects due to short duration of projects and unable to get more hands on knowledge. It would be helpful if someone can guide me on how to upskill myself and what all things I need to be aware so that I can match the requirements as per current market standards ? Also do let me know how much salary can we expect right now based on current market standards? Thanks in advance🙂.