I've seen a lot of beginners (typically those who learn through various YouTube videos and a some online pagess, but not through a systematic guide like a book) having a hard time deciding "what a super simple project" is.
For example: after learning the basic concepts of loop and condition checking, they have no idea how to utilise those in a very simple app. I say "hmm try to write a simple word guessing game... or a simple food ordering app". Usually you'll find various exercises provided in such books.
Ultimately I learned by starting projects that were too large, hitting a roadblock, and stepping back to learn about that thing. Then starting another project and repeating.
This process took years and years before I was reasonably confident in estimating the size of a project. And to be honest even now, nearly 25 years after writing my first tiny cli trivia game, I still get it wrong sometimes, especially in a new domain.
At the end of the day estimation is hard even for veterans of the software industry.
So we can't prove it was due to email content. For all we know it could just be a dude named Richard who throws darts at a board full of usernames all day.