I have forgotten my Minecraft account details. I don't have my email or password anymore. However, the account is still registered on my PC. What should I do? At support I have to enter a valid email and I don't have it anymore
You can enter another email address there that you have access to.
No it has to be an email address that is linked to a microsoft account. Tried it
Then you have to choose change account information, enter the transaction ID and write that you want to change the e-mail address to another, which you write to and then you still write the e-mail address of your account above.
This is the only option because you need to know whether the account really belongs to you.
Unfortunately, I don't know the email address of the account
I don't think there's any other way.