I have no experience with it and cant tell you if it is good or not or how to keep it/make backups, but I guess you can figure this out.
In short: you read some texts out loud and your phone creates a profile of your voice. When it is done, you can type in a text and it speaks in your voice.
I am not sure if this is awesome or creepy, but you might give it a try and see for yourself.
Hey, I think this is a beautiful idea and a lot of people gave good advice on the format. So here is another thing you might look into:
https://support.apple.com/en-us/104993#:~:text=On%20your%20iPhone%20or%20iPad,instructions%20to%20record%20your%20voice.
I have no experience with it and cant tell you if it is good or not or how to keep it/make backups, but I guess you can figure this out.
In short: you read some texts out loud and your phone creates a profile of your voice. When it is done, you can type in a text and it speaks in your voice. I am not sure if this is awesome or creepy, but you might give it a try and see for yourself.