Hey Dawid Woldu, I like your idea/prototype and this interaction pattern might work, not only for power users. My proposal however to improve this interaction: On long tap display the secondary option “draft” or “later” in facebook reaction fashion — expanded above the send button.
I believe this would improve the accessibility and thus usability vastly.
Hope you my idea inspired you a bit. If you can build on it feel free to share with a mention so I’m getting notified.