Glad you got it. I'll leave what I was just going to post for others:
If disabling your extensions doesn't help, here are some other things to try:
You can goto the URL opera://settings/content/all, type x.com in the search field and click "Delete displayed data". Then, repeat for twitter.com for good measure. Then, goto the URL opera://settings/clearBrowserData and clear "Cached images and files" for all time.
Then, goto the URL opera://settings/content/notifications, make sure the default behavior is set to "Sites can ask to send notifications". Then, remove any x.com entries from the allow list by click the 3 dots next to each entry found and clicking "Remove".
Then, restart Opera, log back in to x.com, go to the push notification settings, enable them, click "allow" when asked and see if notifications get enabled as expected.
If that doesn't work, goto the URL opera://settings/clearBrowserData, switch to "advanced" and clear just "site settings" for all time and then try again.
If that doesn't work, you can goto the URL opera://settings/reset and reset just Opera's settings. You won't lose your data, but you might lose your opened tabs.
Also, in "Settings -> System -> Notifications" in Windows, make sure "Notifications" are enabled, make sure "Do not disturb" is disabled and make sure "Opera Browser" is in the list. Then, click on "Opera Browser" and make all the notification settings for it are correct. If Opera doesn't show up in the notification app list, in Opera, goto https://cleverpush.com/en/test-notifications/, click "Greetings", allow notifications and click "Greetings" again. Then, close out of Settings in Windows and go back in to the Notification settings.
You can also restart Windows if needed.
