Unfortunately, in doing so, Signal became Yet Another Messaging App. It really damaged their value proposition in my eyes.
If I need a separate app for SMS, WhatsApp, Messenger, Telegram, Signal, etc, it just becomes a chore to find enough friends willing to move to it exclusively.
The IM ecosystem really needs to be harmonized on the user end. I remember Trillian was this great app back in the day that brokered all your MSM, Google Chat, etc IM accounts into a single app that let you just focus on messaging people and not worrying about what platform was being used. We badly need this again.
What about Mermaid? https://mermaid.js.org/syntax/gantt.html
It supports Gantt charts and has a pretty nice language for modifying chart content once you get used to it.
I use Obsidian with the Mermaid plugin for offline work, but there are tons of good web-based options out there, too.