For some reason KMail does not ship with Kinoite, and it is also not available as a flatpak. It can be installed with rpm-ostree which is what I do now, but I’d prefer not to do that if there is a more standard “correct” way. I can install it in Toolbx of course, but desktop applications don’t appear in the launcher when installed this way (unless there’s some way to do this that I don’t see).
Is layering it the best way to go for this? Or is there some other better way to go about it?
The “Kontact” flatpak contains KMail (along with other KDE PIM applications).
You can add the flathub flatpak repository. Then install the Kontact flatpak, which includes KMail. Be noted that the flatpak of KMail uses SQLite so it might be slow with large datasets.
It does, but it doesn’t seem to work as well as standalone KMail. It doesn’t install as a separate application and I’ve had no luck getting it to accept my imap server configuration (which gives me no trouble in the standalone version).
I sympathize with your issues. Ultimately, I left Kmail/Kontact on my Kinoite instance because the user experience was poor. No separate launchers, poor database performance, IMAP sync issues, etc… I hope KDE’s future Merkuro PIM suite is in a better state. Granted it uses Akondai as well, so IMAP issues may remain.
I have been running the flatpak of Thunderbird on Kinoite for over a year. I think its fine enough for daily work. Plus flatpaks remove the old QT/GTK cross-clutter argument, so that helps.
For GUI apps I also prefer Flatpaks, for their ease of use, their sandboxing features and seamless upgrades, but package overlay with rpm-ostree install can nevertheless be considered a correct way of installing packages on atomic desktops.
I would suggest you to use Betterbird, an improved version of Thunderbird - much more reliable and it works. With TB, I have all the time problems with message rules, closing the program. I have BB for business and TB for private newsletters and other stuff, and BB just works better.