Duplicati (Wikipedia) says you’re talking to the lead developer (2008 Duplicati, 2012 Duplicati 2), however Duplicati 2 is still in Beta, so optional enhancements take a back seat to stable release.
As an open source project, Duplicati has until recently been 100% reliant on the volunteer base, which has always been too small. Volunteers are still sought in all areas if you would like to help.
I’m not going to ask who “they/them” aims at, but could you explain “Telegram-style” if relevant"? Some parts of Telegram are criticized for NOT being decentralized. Some bits are heading there.
Sia Decentralized Cloud
Storj (ex Tardigrade) Decentralized Cloud Storage
might be an answer to some of this request, and I’m not totally sure what underlying wish here is. Possibilities include price, performance, fault tolerance, privacy, etc. Which were the goals here? Possibly some can be more easily achieved (see Issue text) with some less complicated facilities.