I also only use the Lenovo T series. Everything else can't match it.
My questions would be:
- How big do you want the screen to be?
- How bright does the screen need to be?
- How good are your eyes? Does 4K make a difference to FHD or not?
- Is a keypad required? if so, it needs to be at least 16"
I have a few T 480 here that I bought used and they are plenty powerful for photo editing (I use
darktable).
Yes my T14 gen 3 AMD is faster, but instead of waiting 2 seconds I have to wait between 1/2 and 1s for an edit to be applied. Unless that is your full time job the time saved will probably never justify the extra cost.
LibreOffice is good for editing, Calibre for making eBooks and Inkscape for drawing things.
For the Operating system, Ubuntu is pretty easy and well supported, but by default they send more information home than I would like. Since it will not be connected to the internet, that does not matter.
I think 1TB or 2TB SSD is now pretty easy to get for a new laptop. I installed a 4TB SSD since my work produces ridiculous amounts of data and I didn't want to ever have to think about a full disk again.
For the USB-Ports, get a USB-Hub with version 3 or 4. It will be expensive, but then you can plug in as many devices as you want and reduce wear on the ports of the laptop. Maybe even one that also charges the laptop.