Firstly: Am I correct to say after the reporting verbs and after the word "that", it can be followed by any tense?
e.g. On 1 January 2021, you stated that It is your understanding that the company's director has not changed since its establishment.
or On 1 January 2021, you stated that It was your understanding that the company's director had not changed since its establishment.
Secondly, if the above 2 sentences are grammatically correct, any difference in terms of its meaning?
Thirdly: Can I say, if you are using a reporting verb, generally you are using an indirect speech.
You stated that he is crazy. Stated is a reporting verb and this sentence is an indirect speech.