How was the basic system installed? On current installations with newer releases you are getting asked if you want usr merge or not. I have always agreed to that to avoid hasle.
Or is that an upgrade from an older release before usr merge?

Well also from me: I think Chimaera would be a good compromise. Longer maintenance but still the old design of Evolution though a bit newer than the Beowulf package.

There is no way to avoid this Windows style decoration in Evolution on Daedalus. Stay on Beowulf or at the most upgrade to Chimaera.

That command apt -t daedalus-backports install will automatically pull in all dependencies as listed in the package.

Additional packages that are not dependencies must be installed with the same method as kicad.

Yes, as long as backports remains enabled in the sources.list.

Nothing but: lately the update routine behind linux-image-amd64 just keeps max 3 kernels. On my Daedalus PC I have the 6.1.0-13, and 6.4 and two 6.5 kernels from backports. And my linux-image-amd64 is from backports so my kernel updates all come from there now. The 6.1 kernel history has been deleted by suggested apt autoremove actions.

And all of this without grub customizer (which caused me a lot of grief, so I think this tool cannot be recommended).

Nothing except the standard solution is to let the meta-package linux-image-amd64 take care for updates. At least I am doing so. 
You always are able to install kernels that are listed in the repository. I personally have no idea how that looks like.

The kernel comes down from Debian. So a bug report into Debian would make sense. Though if I read the messages right the problem really is at kernel.org.

Looks like your issues add to the network problems seen by others with the -15 kernel.

Well, on my Daedalus fdisk still is present as a Devuan forked version. Maybe your version still was the Debian based one? You should be able to re-install fdisk.

I am using grub with luks and LVM, works fine for me for many years by now.

Looks like 6.1.0-15 is available by now.

Looks like that was a typical temporary hickup of the testing repo and its mirrors.

Glad that its solved now.

Maybe the mirror isn't up to date? Perhaps you try deb.devuan.org/merged instead?

Well, the netinstall is meant for computers which have a working (wired) network connection to download everything that is not on this small media. So if the wifi requires drivers most likely they are not included. You either need to use the CD or DVD version, or identify the chip used.

Please run and poste output here. inxi could be an alternative.

# lspci | grep network
# lsusb | grep network
# inxi -Fz

Try the netinstall ...