I suppose to many this may be childishly obvious, but in case it helps anyone, here are two things I have learned.
The first is to do with the Kobo e-reader. I find the Plato reader much nicer than the regular one it comes with, and the way to install it is given here
https://www.mobileread.com/forums/showthread.php?t=314220
The simplest is to use the install script provided here:
https://www.mobileread.com/forums/showpost.php?p=3797096&postcount=2
I first tried installing KOReader, which a lot of people seem to like, and you can install both of them from the install script, but it led to a very messy layout, so I reset it to factory and then installed just Plato. This is on the Kobo Aura One, which I find perfect. Its small enough to handle, but it has a 7.8 inch screen which is big enough to read comfortably on for a long time. You can control the amount of blue light, as well as brightness.
The other thing about the Kobo is the registration procedure, and there is a very simple way of avoiding having to do this. During the activation you choose 'no wifi'. You can then access the files on the device from terminal or file manager. So you open a terminal, enter the folder containing KoboReader.sqlite, and run the following:
sqlite3 KoboReader.sqlite "INSERT INTO user(UserID,UserKey) VALUES('1','');"
Restart and you have activated. Wonderfully simple, private, and it avoids having to mess with the sqlite database.
The second thing I learned was about AMD and suspend. Having put together a new machine with an AMD processor I was expecting to be able to use xautolock, with pm-suspend as the lock program. But the result was that it did indeed suspend, and when a key is hit, it seems to wake, but the screen remained black.
I did two things after which it works flawlessly, but I am not sure which of them was effective, or whether you need to do both. I installed the AMD and RTL non-free firmware. And I also took the kernel to the testing branch of Debian, and the way you do this, without taking the whole installation to testing, is to modify /etc/apt/preferences as follows (I had to create since not already there):
Package: * Pin: release a=bullseye Pin-Priority: 500
Package: linux-image-amd64 Pin: release a=testing Pin-Priority: 1000
Package: * Pin: release a=testing Pin-Priority: 100
So the idea is that it only takes the kernel updates from testing. And amazingly enough this has worked, its now on 5.19 whereas bullseye came with 5.10, and xautolock loads at startup and works perfectly!
Two small victories.
Peter