Yes, I use Tab XC for my samples and in training. The software I use is Mobilesheet for e-readers, which can be obtained directly from the developer.
It has backlighting. As colour e-inks generally have thinner displays than SW displays, the backlight of my Tab XC is always on at about 70-90% brightness.
The battery performance is very good. On a full charge, in aeroplane mode without WLAN and BT, I still have approx. 50-70% battery after a 5-hour test, depending on how often I use the stylus.
Inspired by your question, I wrote a review ☺️ I'm very satisfied so far, the battery lasts so long that the only danger is that I forget to plug it in from time to time. The backlight can be finely adjusted and has worked for me in every situation, from complete darkness to bright sunshine. A note: If you don't need colours explicitly, you can get the monochrome version with better contrast for a little less money - apparently not at Digitec
I only need the tablet for sheet music. Two music clubs, three different instruments, various musical projects, church events, "Stubete" etc. I also have MobileSheets as software - like almost everyone else.
The thing always has the perfect lighting, from gloomy churches to glaring sunshine outdoors. The surface is matt and therefore not reflective. Without the backlight (not necessary when rehearsing), the battery lasts almost forever with the WLAN switched off. This means I only charge the tablet before important events.
Compared to cheaper tablets, which usually have a less favourable display format (16:10), the slightly higher price is worth it.