Earlier quoted context omitted.
Telegram has similar "Saved Messages" feature.
Can you expand om that? The way I send something to myself on Telegram is by posting something in a group, of which I'm the only member.
"Saved Messages" looks like a private chat that only you can see. You can drop messages or files in there, or forward them there from other chats, and access them from any other device.
It's pretty similar to what you describe.