i see, save/load game, i always recommend using plugin, many people stuck with this save and load of the game
GitHub - AdamKormos/SaveMadeEasyG3: An easy to use, versatile Save/Load System for Godot 3 inspired by the simplicity of Unity’s PlayerPrefs. Supports nested variables, Resources, Arrays and encryption. here is for godot 3
the example implementation of the plugin is here File.open(path, FileAccess.WRITE) is not truncating - #7 by zdrmlpzdrmlp
but it’s in godot 4 script
also it seems like you are trying to save a whole node/scene data. is that necessary?