I would love to have this feature. I have posted a similar feature two years ago but no feedback so far from the SmartGit team:
https://smartgit.userecho.com/en/communities/1/topics/1129-log-view-open-multiple-submodules-at-once

Authentication on GitHub using Username/passwords from SmartGit will no longer works after August 13th 2021 which means that this workaround will no longer works. We will need a more permanent solution for being able to switch between GitHub accounts from SmartGit. See reference:

https://github.blog/2020-12-15-token-authentication-requirements-for-git-operations/

The fact that the submodules are "closed" by default hides some useful information on the submodule element in the log:

- There is no visual indication of the status of your current branch compared to the tracked branch (green and orange arrow)

- There is no indication on which branch is checked out or if the head is detached.

Having a way to easily open all submodules at once would really be appreciated.

We are able to select multiple repositories and with the context menu click on the "Open Repository" button. Even though we can select multiple submodules there is no option to open them. Having a similar option for opening submodules could be helpfull and save a lot of times when we want to monitor a lot of submodules.