> The reason why my IP address is visible is because Apple Mail sends emails with SMTP.
Unless you use a proxy, your IP address is visible to an SMTP server, just like it's visible to an HTTP server when you use a web browser. This is not specific to Apple Mail or to Gmail.
Yeah but I think Gmail seems to actually just keep that header rather than nuking it. To be fair I don't entirely know what I would do to fix it since (like the post) this seems like there aren't many good options here.
I clearly remember many years ago that this wasn’t the case with Gmail, when looking for the source IP address in a case involving harassment of a person. I could only get Gmail’s own IP address in the headers from the multiple emails I examined at that time.
Nevertheless, as js2 said in another comment, it’s your mail provider (in this case Gmail) deciding whether to include the sender’s IP address or not.
> The reason why my IP address is visible is because Apple Mail sends emails with SMTP.
Unless you use a proxy, your IP address is visible to an SMTP server, just like it's visible to an HTTP server when you use a web browser. This is not specific to Apple Mail or to Gmail.