I did a little research and ran Opera GX in debug mode, the following errors were written out when closing:
[60588:35075:0222/114603.524404:ERROR:partner_bookmarks_utils.cc(263)] Unable to read partner speeddials file.
objc[60595]: Class WebSwapCGLLayer is implemented in both /System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.framework/Versions/A/Frameworks/libANGLE-shared.dylib (0x23d3eaf88) and /Applications/Opera GX.app/Contents/Frameworks/Opera Framework.framework/Versions/95.0.4635.54/Libraries/libGLESv2.dylib (0x108ec3b30). One of the two will be used. Which one is undefined.
[60588:137251:0222/114610.598918:ERROR:gcm_store_impl.cc(953)] Failed to restore security token.
[60588:259:0222/114610.926165:ERROR:CONSOLE(22)] "Uncaught SyntaxError: Unexpected token 'export'", source: chrome://resources/js/assert.js (22)
[60588:259:0222/114610.926190:ERROR:CONSOLE(5)] "Uncaught SyntaxError: Cannot use import statement outside a module", source: chrome://resources/js/util.js (5)
[60588:259:0222/114610.971285:ERROR:named_platform_channel_mac.cc(69)] bootstrap_look_up /Users/*/Library/Application Support/com.operasoftware.OperaGX/oauc_pipe_r: Unknown service name (1102)
[60636:259:0222/114610.995833:1019555219393:ERROR:icu_util.cc(181)] icudtl.dat not found in bundle
[60636:259:0222/114610.996203:1019555223266:ERROR:icu_util.cc(243)] Invalid file descriptor to ICU data received.
[60636:9219:0222/114611.755288:1019573441635:ERROR:named_platform_channel_mac.cc(44)] bootstrap_check_in /Users/*/Library/Application Support/com.operasoftware.OperaGX/oauc_pipe_r: Service is already active (1103)
[60636:9219:0222/114611.755433:1019573444975:ERROR:ipc_thread_impl.cc(99)] Unable to create IPC as server!Pipe name used: /Users/*/Library/Application Support/com.operasoftware.OperaGX/oauc_pipe_r
[60588:259:0222/114634.104928:ERROR:fallback_task_provider.cc(124)] Every renderer should have at least one task provided by a primary task provider. If a "Renderer" fallback task is shown, it is a bug. If you have repro steps, please file a new bug and tag it as a dependency of crbug.com/739782.
sysctlbyname for kern.hv_vmm_present failed with status -1[60595:259:0222/114642.466232:ERROR:shared_image_manager.cc(251)] SharedImageManager::ProduceOverlay: Trying to Produce a Overlay representation from a non-existent mailbox.
[60595:259:0222/114642.466257:ERROR:skia_output_device_buffer_queue.cc(332)] Invalid mailbox.
[60688:259:0222/114653.250123:1020569328091:ERROR:icu_util.cc(181)] icudtl.dat not found in bundle
[60688:259:0222/114653.251891:1020569363532:ERROR:icu_util.cc(243)] Invalid file descriptor to ICU data received.
Among other things, I noticed the point "Failed to restore security token" here, which means: "This error suggests that the browser was not able to restore a security token, which can cause issues with accessing certain websites."
Which could be a possible mistake, which is why Opera has no way to store such things as registrations, But that's just a guess, at least this seems to be a general Mac problem, as older versions such as 89.0.4447.98 are also affected