With the exception of the standalone apps and the GrapheneOS apps repository, most GrapheneOS stock apps are subpar compared to the OS itself. The files, dialer, and settings apps are up-to-date, since Google uses them elsewhere, but the calculator, clock, contacts, and messages apps still don't even have a dark mode. The gallery app, by contrast, has only a dark mode that predates material design, as it seems it hasn't been updated since its release or before it. There is no calendar app to speak of, because the one that is included in the system but hidden has a similar out-of-dateness problem as the Gallery app. There's also a search app that is included but also hidden with the stock launcher. I was told I could install a different search provider, but I don't know how to do that because from what I can tell the concept has pretty much been abandoned in modern Android. The one included seems to be the exact same one as from the first versions of Android, literally.
The apps that are included do work to a reasonable, but still low degree. It's quite disappointing to be using Android 12, with material you in the OS and even some user apps now, and yet not even have the first version of material design in all apps, or a dark mode in all apps, let alone material you in all apps.
If you're looking to replace them, you're going to be faced with a similar problem, as other versions of Android that maintain a more up-to-date copy of their stock applications only release them in the form of source code, the Google apps are all proprietary, and no independent developer is maintaining a lot of the stock apps.
You can find suitable replacements for the files and dialer apps, but since those are fine it makes no sense to do so. But if you wanted an independently maintain replacement for the calculator, clock, contacts, or gallery apps, you'd be out of luck. There are replacements for the messages apo though.
For the remaining apps, you pretty much only have the option of either using the stock app, and living with its outdated design and lack of features, or installing the versions from the simple mobile tools project, since they're the only ones to have maintained replacements for the aforementioned. However, if you do that, you'll have to install most or all of them from F-Droid unless you also want to purchase them from the proprietary Google Play Store. And you'll have to additionally install or purchase their thank you app to be able to then switch on the material you theme in each app individually. You can also change the icons, but they don't change in context or file picker menus, so you'll have an inconsistency if you do that.
Obviously all of that's not an ideal solution either, so you're basically left with having to decide between two bad options. I'm nonetheless keen to hear your thoughts on this. If there are other alternative apps I haven't considered, or if, like me, you think GrapheneOS should also put work into maintaining or themselves replacing their stock apps for everyone who uses the OS.
As for the calendar, I use etar, but I think if the stock calendar app is not going to be included, an option such as etar should become the official and the included version.
Anyway, thanks for reading this and thank you in advance for any and all feedback. And thank you to the GrapheneOS team for using and promoting open source forum software!