@JessDail I'm linking to the web version of Joplin mobile (app.joplincloud.com, currently in beta) as another possible way to run Joplin on Android 12.

@JessDail To clarify, when the app goes into the background, does Joplin show up as still running in the app switcher, or does it need to be completely re-launched from the app switcher? (Does this seem to be an application crash?)

@JessDail If you eventually attempt a new sync from a different profile, consider also enable the beta encryption method (settings > sync > advanced) (related: https://discourse.joplinapp.org/t/beta-encryption-switch-on-what-to-consider/43226, https://discourse.joplinapp.org/t/final-report-of-the-native-encryption-project/40171). Beta encryption should be significantly faster than the current default encryption method. However, it would need to be manually enabled on each device and for the performance improvement, notes would need to be re-encrypted from a desktop app (in settings > encryption > advanced).

@JessDail Yes — it's possible to create new profiles on mobile (see the instructions included in my previous reply). Given the number of items (33,000!), it might make sense to get more information about the sync issues first. If the notetaker still has the "Some items failed to be decrypted" banner, in the latest pre-release, clicking on it should now categorize new decryption errors by type. Are there any decryption errors with error message descriptions on this screen?

@JessDail It may also be possible to get more information about the issue from "configuration" > "tools" > "log" > "errors only" (at the end of the focus order). However, 1) it may be difficult to find the relevant error in the log file (if any) and 2) if the crash is caused by native Android code (as opposed to React Native-related JavaScript), it might not be included in the log.

@JessDail One thing to try might be to set up sync from a new profile and set "attachment download behavior" to "auto" or "manual". This may help if sync issues are related to a particular attachment. To do this:
1. Create a new profile (configuration > tools > manage profiles > new profile, enter a profile name, click "save").
2. Re-launch Joplin.
3. Go to configuration > synchronization > advanced, change "attachment download behavior" to "auto".
4. Select the sync target and start sync.

@JessDail If the crash is related to the animation crash mentioned above, opening settings before syncing (which dismisses the sidebar and its "syncing" animation) may prevent the crash. (If this is the case, please let us know!)

@JessDail We have received issue reports related to crashes on Android 12 in the past (see [upstream issue: Animation-related crashes](https://github.com/facebook/react-native/issues/37267#issuecomment-1596669332) and [related patch](https://github.com/laurent22/joplin/blob/dev/.yarn/patches/react-native-npm-0.74.1-754c02ae9e.patch)). [Another recently-reported crash](https://github.com/laurent22/joplin/issues/12050) was related to `react-native-quick-crypto` and should be fixed in the just-released Android 3.3.5 beta.

@JessDail I think that's the same package — for me, "flatpak install joplin" prompts to install the same package as above (with "flatpak install net.cozic.joplin_desktop").
If you haven't tried this already, uninstalling, then re-installing the Joplin Flatpak might help. I was able to do this by:
1. Running "flatpak uninstall net.cozic.joplin_desktop"
2. Running "flatpak install net.cozic.joplin_desktop"

@JessDail I've installed Fedora 41 MATE in a virtual machine and installed Joplin from a Flatpak. For me, it works with Orca. For comparison, here's how I installed it:
1. From MATE Terminal, installed flatpak with "sudo dnf install flatpak"
2. Added Flathub as a flatpak remote with "flatpak remote-add flathub https://dl.flathub.org/repo/flathub.flatpakrepo"
3. Installed the (unofficial) Joplin Flatpak with "flatpak install net.cozic.joplin_desktop"
4. Opened Joplin with "flatpak run net.cozic.joplin_desktop"