I am sorry that I can not provide any informations as stated in the template, since there is no such thing. Instead I will proceed providing information.
I am currently using ArcaneChat and DeltaChat on an AOSP-derived system. I would also like to use it on Desktop. Since npm is not an option and electron nothing less than a blatant offence to humankind, I went for dreamer. But it has no gui for account management. That I already had DeltaChat is what dreamer expects, I guess.
Therefore, I expect the format for the accounts.toml to be easily found in some documentation.
I would not use dreamer unless you are a developer that wants to maintain it. it uses an old core version that might bring compatibility problems when using it together with newer clients.