How to say "free yourself" in Mandarin"?
You can use 釋放自己, It's OK. Similar: 釋放自我, 解放自己(我), 開放自己(我), etc...
You could use 釋放 based on context.

Release from Prison, you can use 釋放. e.g. 他剛從牢裡釋放出來。

Release the Pressure, you can also use 釋放. The Pressure could be mentally or mechanically(like tire pressure) e.g. 他用大吃大喝釋放工作壓力. 這輪胎必須釋放一點過高的胎壓.

Release something, e.g 這公司有新的工作機會釋放出來了. (This company has released new job opportunities.)