You mean odometer, resetting the speedometer wouldn't be a bad thing.
The calibre content server also serves OPDS. Once you have a OPDS server in place you'll need to point a capable reader at it, but after that syncing and reading happens in the reader.
Typically xdg-ninja will tell you how to set things up so as many dot files and directories as possible end up in the correct xdg location instead of cluttering up the top level of your home directory.
self hosted alternatives for smart home and porn
How does self hosted porn even work and how am I the first person to notice that sitting there and mention it?
NetworkManager (network interface/connection management)
Pretty sure you mean systemd-networkd here. I find systemd-networkd to be very nice for headless systems, but NetworkManager seems to be a better fit for desktops because of the integrations it has available with KDE/Gnome/system tray
steamtinkerlaunch makes running Skyrim with ModOrganizer2 very simple. Other external programs will probably still be tricky though
Ubuntu has significant differences from Debian so it wouldn't make much sense to be able to install it as a "flavor" of Debian. However, *Ubuntu are pretty much already metapackages on top of regular Ubuntu. So instead of having different installers for each one, you could just make it an option during install and provide an easy means to add/switch other options later
I've always used this docker image to do pg upgrades. It runs pg_upgrade to recreate the system tables and copy the user tables (which normally don't have any storage changes). It does require that the database isn't running during the upgrade so you're going to have a bit of downtime. Make sure you redo any changes to any configuration files, especially pg_hba.conf