After last update of Opera, Reader mode is not available anymore.

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@burnout426
Thanks for the reply.
I have Avast antivirus on my pc. It was set to auto update, but for some reason the June program update was still pending. After performing it, all Opera features were restored, except the availability of "Reader Mode" from the lateral bar.
@burnout426
Thanks for the reply.
I have Avast antivirus on my pc. It was set to auto update, but for some reason the June program update was still pending. After performing it, all Opera features were restored, except the availability of "Reader Mode" from the lateral bar.
After a routinary CCleaer cleanup, Opera doesn't save new bookmarks and existing bookmarks dated after July, 3 are missing. So I tried to use "restore data and settings", but after the reset, not only were previous problems not resolved, but now I can't save my browser settings. When I restart it, Opera returns to default.
I imported bookmarks previously saved in .html but after restarting Opera they are missing.
I noticed that files named Bookmarks aren't stored any more in
C:\Users\Username\AppData\Roaming\Opera Software\Opera Stable\Default
What's going wrong? Another minor issue ("reader mode" not available in lateral bar) started after updating Opera about 10 days ago.
Should I uninstall and reinstall it?
like any other page don't allow Reader Mode after updating to Opera One version 111.0.5168.55.

@kajikiaaudax
After update, no page on sites I usually visit can be opened in reader mode on my Opera browser. Previously, I hadn't any issue about it.
@leocg
As all YT videos inside a playlist have &list=PL in the address, I used Bookmark Dupes extension in Expert mode to find all entries matching it. Then I manually deleted doubled ones.
Nex time before bookmarking new videos inside playlists I'll look in the address bar to see if
&list=PL is in, and delete it and all letters following.
@joshsiddle8 "Bookmark Duplicate Cleaner" is only for Firefox and discontinued.
I tried "Bookmarks Manager and Viewer" but didn't find mention of the feature for finding duplicated bookmarks in the extension page.
https://webextension.org/listing/bookmarks-manager.html#:~:text=To validate%2C first%2C select the,at the top-right corner.
Is there a feature for finding bookmarks with duplicated titles or addresses?
@leocg I don't include time, bookmark links are stored automatically with a suffix that changes every time they are saved (i'm not pretty sure it depends on the time reached in playback or other).
For example:
As I have thousands of them, I'd like to get a bookmark manager which easily cleans up dupes with same title but different links.