The default reply header goes like "XYZ wrote:". It's a simple line, and the entire quoted message content is indented by a quote character or element. Signature goes way to the end. That's the usenet quoting style. It's nice if everybody does that, but in reality, nobody does it and it results in TOFU which is unreadable.
Outlook uses a different style. It doesn't indent the quoted message but moves it to the end and inserts a header that includes some useful information, like the sender name, address, and date and recipients. This is the common and expected style in business communication. Sadly, almost everyone uses Outlook and expects the same style. But it's actually very practical. It's just Thunderbird that can't achieve this without extensions (which all broke in the past).
There are some hacks with hidden options in Thunderbird, but they have negative side effects like removing all existing quote indents even in the quoted content! So Thunderbird will then manipulate the quoted message (and make quotes indistinguishable)!
Also, the date format must be configurable, or at least universally understood. When I'm writing to other countries, my local date format will not be understood there. This is also very short-sighted.