Dude that sucks! Shame SimpleX doesn't have like a master password or anything. My wife recently got a new phone and the simpleX migration went really smooth, but it assumes you have the old phone and the new one at the same time. Guess you are shit out of luck in that scenario
Since I had to lose tens of gigabytes worth of data just to get back into MY phone, I am no longer risking using SimpleX nor XMPP in any capacity, with the former being eschewed in their entirety (sorry to both nostr:npub17l2zfdwp4f28llxjqs6udvtda8z6k6th2pdmdfjvlpcwxcvv285qw6v5xu and nostr:npub1q6ya7kz84rfnw6yjmg5kyttuplwpauv43a9ug3cajztx4g0v48eqhtt3sh) and the latter being used on PC exclusively until I decide on when to get rid of both accounts down the road (on mobile, I was using Conversations while using xmpp.earth solely on PC originally).
Threema is on thin fucking ice now, with a decision as to whether I begin to use Proton Drive (or do local backups FAR more often now) pending.
Discussion
When everything fails, blame Google.
This isn't the fault of the apps or the services, yet I already had a similar experience on my computer with SimpleX that put me on edge with the latest account (and profiles) of mine that I lost because of something that I could NOT control this time; with experience like that, along with the fact all the lost data had been recovered from my older Pixel I spent a good amount on to repair, it leaves me feeling far more bitter and less inclined to live and let live than I may have been after a few days.