adding shortcuts to dedicated chats to the homesscreen is already possible for recent chats with somehow recent androids 
- long tap the “Delta Chat” icon, you see the most recent chats there
- drag the desired chat to the homescreen
by the way, on iOS, there is a similar option using “Add to Widget” from the chat’s profile
i directly created a little tip on our favourite social media for that: bjoern: "💡did you know ... you can have recent #deltachat …" - Mastodon