Comment 3 for bug 1970248

GNOME 40 and newer doesn't use /usr/share/applications/defaults.list file, I think this is the main issue why deb files are opened by Archive Manager, for more info look at

https://help.gnome.org/admin/system-admin-guide/stable/mime-types-application.html.en

Quick fix could be to change the name of /usr/share/applications/defaults.list symlink to mimeapps.list , but I'm not 100% sure, because there is a line in /usr/share/applications/gnome-mimeapps.list
application/x-deb=org.gnome.FileRoller.desktop

The /usr/share/applications/mimeapps.list and /usr/share/applications/gnome-mimeapps.list files specify which application is registered to open specific MIME types by default. These files are provided by the distribution.

To override the system defaults for all users on the system, you need to create a /etc/xdg/mimeapps.list or /etc/xdg/gnome-mimeapps.list file with a list of MIME types for which you want to override the default registered application.

Files located in /etc/xdg/ take precedence over files found in /usr/share/applications/. Additionally, /etc/xdg/gnome-mimeapps.list takes precedence over /etc/xdg/mimeapps.list

Btw, there is a bug #1559129 (Replace defaults.list by mimeapps.list) already reported few years ago by Ubuntu developer, but it seems someone forgot to fix that :(