Couldn't unlock phone and stuck in a reboot loop after my battery completely died once, sideload doesn't fix

So one day my Pixel 3a's battery died (and since I quite urgently need the phone) I force it to boot up (cause sometimes you can still juice out a few minutes) but as it booted up, the wallpaper displayed correctly but the date/time is wrong, when I drag down the control center it's blank (though it sometimes pop up fine, but I think just once), stuck within plane mode (though I doesn't turn it on prior the shutdown), battery showing blank while in power off it clearly shows it charged to certain percentage of battery, and unlocking doesn't do anything. Then after a while the phone just reboots itself again and now I'm stuck within this loop. My first thought is to just re-install the system through adb sideload as perhaps something corrupted (as once in a while, after many reboot a recovery mode like notice will pop up stating that the system might be corrupted and if you saw this message multiple times, you might need to try factory resetting). But now I sideload the newest pixel 3a official image (11.0.0 (RQ3A.210805.001.A1, Aug 2021)) I'm still stuck in the loop I described above, I still can't unlock my phone and my phone just keeps rebooting it. Previously (prior to sideloading) I remember recovery mode showing: > WARNING: Previous installation has failed. > Your device may fail to boot if you reboot or power now. (Though it may be result of me for doing other thing like testing apply update from SD card or letting adb to timeout as I forget to download the image first.) But it seems that after sideloading the warning doesn't show up, so perhaps I did sideload it correctly? (So as getting a 0-return value) But still the issue persists. But since I've gone to the newest version of the image, it seems that I couldn't downgrade it anyway. So is there any other way to solve my problem (besides factory resetting it as I kinda want to maintain the data within it, and I still couldn't access my data through USB currently). I don't think I've enabled USB debugging prior this event, so unless enabling it is possible to achieve without needing to enter the system (like settings), otherwise it makes no help. I thought sideloading official image meant the system will be re-install completely such that any corrupted file would be fixed. Is it the case? And since there seems to be no cache in Pixel 3a, does it means something ***other*** than system might have corrupted? And if so is there still hope to recover it?