At the moment, it seems to me that fuzzilli implements read and write operations on the __proto__ property , and does not implement delete operations on it.
In addition, in practical use, the __proto__ property points to a complete object literal. It is often necessary to perform more granular operations, such as addition, deletion, or modification, on this object (where modification and addition share the same syntax). Below are examples of each operation :
obj.__proto__.a = 1
x = obj.__proto__.a
delete obj.__proto__.a

Similarly, the implementation of the constructor's prototype is missing, as exemplified by the following:
Class.prototype = {}
obj = Class.prototype
delete Class.prototype
More granular property manipulation, for example, is as follows:
Class.prototype.a = 1
x = Class.prototype.a
delete Class.prototype.a

So here we add some corresponding codeGenerators to cover the above scenarios.