Tested both on a fresh Debian testing install as well as an update to an existing Ubuntu 24.04 install. Installing the .deb version fails at the same point.
~ > sudo apt install opera-stable
Installing:
opera-stable
Recommended packages:
chromium-codecs-ffmpeg-extra
Summary:
Upgrading: 0, Installing: 1, Removing: 0, Not Upgrading: 24
Download size: 0 B / 133 MB
Space needed: 361 MB / 118 GB available
Preconfiguring packages ...
Selecting previously unselected package opera-stable.
(Reading database ... 143088 files and directories currently installed.)
Preparing to unpack .../opera-stable_124.0.5705.42_amd64.deb ...
Unpacking opera-stable (124.0.5705.42) ...
Setting up opera-stable (124.0.5705.42) ...
update-alternatives: error: alternative path /usr/bin/opera-stable doesn't exist
dpkg: error processing package opera-stable (--configure):
installed opera-stable package post-installation script subprocess returned error exit status 2
Processing triggers for hicolor-icon-theme (0.18-2) ...
Processing triggers for gnome-menus (3.38.1-1) ...
Processing triggers for shared-mime-info (2.4-5+b3) ...
Processing triggers for mailcap (3.75) ...
Processing triggers for desktop-file-utils (0.28-1) ...
Errors were encountered while processing:
opera-stable
Error: Sub-process /usr/bin/dpkg returned an error code (1)
Digging into the details, the install script fails where it tries to register Opera with update-alternatives
update-alternatives --install /usr/bin/x-www-browser x-www-browser /usr/bin/opera-stable
The problem here is that /usr/bin/opera-stable was never created, only /usr/bin/opera . Manually creating opera-stable does fix that problem, but the post-install script then still fails where it tries to symlink /usr/share/man/man1/opera-stable.1.gz. This file does not exist within the .deb. I stopped my debug session there.
The binary /usr/lib/x86_64-linux-gnu/opera is installed, so you can actually open Opera v124. But it opens without an application id. This means it does not open with the Opera icon but with the generic one. Grouping different Opera windows consequently fails as well. If you've pinned the opera launcher to the dash it will not open there.
It also seems to have problems finding the libffmpeg.so, so many video formats fail.
Overall the .deb version is as broken as the snap version atm. There's no sense using Opera in this broken state, so I hope this will be fixed soon.