This was my question and wasn't clear to me at all from the announcement -- that there was a roadmap for my own (not Signal cloud) cross-platform, incremental, secure encrypted backups as well.

(That presumably would let me store as much as I wanted without a fee).

I wasn't even aware of the existing "local backup feature" making it more confusing -- but reading the announcement I was like, wait, the only backups avail are in Signal cloud? that doesn't seem right, why can't I get my own backup file to do what I want with?

I feel like I now understand, thanks! Personally would recommend the announcement at least reference this future roadmap too, for clarity.