Only in the Beta Android app for now... Signal is around for what, a decade now? And they still can't (or rather, refuse to) do the basic "copy the SQLite DB file to a folder". Edit: and even this beta feature is some bullshit proprietary thing with their own cloud and subscription rather than simply "let me export the DB file and stick it in a cloud provider of my choice".
Last time I had to reinstall my phone I ended up finding an implementation of their phone-to-phone transfer protocol to emulate a "new" device I'm transferring to just to get a dump of the data (I'd share, but don't want them to close this option, since clearly the lack of export option is very much intentional).
Then I deleted Signal and begrudgingly moved to WhatsApp (in addition to iMessage which I've already been using).
Never on iOS or any other Apple platform. Signal is designed not to be able to backup to iCloud either. The only option iOS users have had over the last few years is to do a device to device transfer where both phones are expected to be in physical proximity and it takes hours to transfer the data. Lost phone has meant losing all chats.
WhatsApp, which is infamous by association with Meta, backs up to Google Drive or wherever.
Last time I had to reinstall my phone I ended up finding an implementation of their phone-to-phone transfer protocol to emulate a "new" device I'm transferring to just to get a dump of the data (I'd share, but don't want them to close this option, since clearly the lack of export option is very much intentional).
Then I deleted Signal and begrudgingly moved to WhatsApp (in addition to iMessage which I've already been using).