Can't upgrade to 23.04, potentially caused by Opera

I'm trying to update my 22.10 to 23.04, but I get the following error:

Continue [yN] y
Get:1 Upgrade tool signature [819 B]                                                     
Get:2 Upgrade tool [1,260 kB]                                                            
Fetched 1,261 kB in 0s (0 B/s)                                                           
authenticate 'lunar.tar.gz' against 'lunar.tar.gz.gpg' 
extracting 'lunar.tar.gz'

Reading cache

Checking package manager
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Hit http://gb.archive.ubuntu.com/ubuntu kinetic InRelease                                
Hit http://gb.archive.ubuntu.com/ubuntu kinetic-updates InRelease                        
Hit http://gb.archive.ubuntu.com/ubuntu kinetic-backports InRelease                      
Get:1 https://download.opensuse.org/repositories/home:/npreining:/debian-ubuntu-onedrive/xUbuntu_22.10 ./ InRelease [1,604 B]
Hit http://security.ubuntu.com/ubuntu kinetic-security InRelease                         
Fetched 1,604 B in 0s (0 B/s)                                                            
Reading package lists... Done    
Building dependency tree... Done 
Reading state information... Done
Fetched 0 B in 0s (0 B/s)                                                                
cat: /tmp/opera.timestamp: No such file or directory
sh: 1: [: -ne: argument expected
rm: cannot remove '/tmp/opera.timestamp': No such file or directory
Exception during pm.DoInstall():  E:Problem executing scripts DPkg::Post-Invoke 'if [ `stat -c %Z $(readlink -f $(which opera))` -ne `cat /tmp/opera.timestamp` ]; then /root/.scripts/fix-opera.sh; fi; rm /tmp/opera.timestamp', E:Sub-process returned an error code

Error in sys.excepthook:
Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeViewText.py", line 138, in _handleException
    apport_crash(type, value, tb)
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeApport.py", line 57, in apport_crash
    apport_excepthook(type, value, tb)
TypeError: apport_excepthook() missing 1 required positional argument: 'exc_tb'

Original exception was:
Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/lunar", line 8, in <module>
    sys.exit(main())
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeMain.py", line 241, in main
    if app.run():
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeController.py", line 2042, in run
    return self.fullUpgrade()
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeController.py", line 1871, in fullUpgrade
    if not self.doPostInitialUpdate():
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeController.py", line 906, in doPostInitialUpdate
    self.quirks.run("PostInitialUpdate")
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeQuirks.py", line 99, in run
    func()
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeQuirks.py", line 126, in lunarPostInitialUpdate
    self._maybe_prevent_flatpak_auto_removal()
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeQuirks.py", line 519, in _maybe_prevent_flatpak_auto_removal
    self.controller.cache.commit(
  File "/tmp/ubuntu-release-upgrader-wqzyt1tn/DistUpgrade/DistUpgradeCache.py", line 309, in commit
    apt.Cache.commit(self, fprogress, iprogress)
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 668, in commit
    raise SystemError("installArchives() failed")
SystemError: installArchives() failed

Initially, I had Opera installed from a .deb file and I thought removing and reinstalling via Snap might help, but I'm getting the same error. When the Opera was uninstalled, it still didn't work, although I got a different error (sadly can't remember what it was).