Are Git submodules really that bad? Really? Maybe it's me that haven't yet discovered their true dark side. They're not perfect, but works well for mid-sized projects at least.
Git has been adding more config settings to try to make it less painful, such as submodule.recurse, but that slows down most git-command significantly and the truth is most repos don't actually need to recurse - they just need the top level. So instead people end up writing aliases to try to handle it, which works ok, but it's brittle and people have to know to do it.
And if you have your repo on GitHub, they don't do some simple things that could have made it easier. For example, they could let the repo owner make the git-clone copy-to-clipboard thing have --recurse-submodules in the command you copy, so that cloning will do the right thing. But they don't. I understand why git itself doesn't want to make such things automatic, but GitHub could do it for at least private enterprise account repos.
BTW, I am _not_ advocating whatever this "Git X-Modules" thing is that the link points to. I have no idea what that is, never used it, and don't plan to.
Say you're git, and someone has a submodule that goes from having:
sub/
.gitignore = a/ignored.txt
a/
tracked.txt
ignored.txt
sub/
b/
tracked.txt
Git's answer to every single question like this is to either fail to perform the submodule version change, or leave a now-untracked-and-not-ignored sub/a/ignored.txt file in the directory, which leaves you with an un-clean checkout that it'll warn and complain and possibly conflict on.
It's highly unergonomic, but reliably avoids silently doing anything that might cause you to lose data. The awful ergonomics are what people generally hate about it. They'd rather it made some consistent decisions so it Just Worked™ in nearly all cases. But that's not Git-like.
They're still pretty annoying to actively work in.
We keep only DTOs in sub-modules so you really update it if you change property on some communication objects.
This way you also don't want them to be invisible - you really want to see and have people notice this was updated and actively choose what to do with it.