Currently, when searching opened tabs (using % on the address bar), the tabs that are found are from the same container (or a different device). Tabs from other containers in the same browser are not visible from the tabs search.
As I have a lot of opened tabs, I often used the tab search to navigate between my opened tabs, but when I am on a containerized tab, like Facebook, the fact that the other tabs do not show up on the search makes it a lot less convenient. In some cases, it means that I have to open a new tab in the container I want, then search on that tab, then close the new tab.
The tab search should work across containers. Since it shows tabs opened from another device no matter what container we are on, it is likely not a security concern, and it would make the tab search a much more convenient tool to switch between opened tabs.