Yes, they do have a Linux version and it is easy to install. I did it several times, not for myself but for my neighbor who always wants to create a photo album of their holidays.
What I do is I install it without sudo so it gets installed in a directory inside your home folder, that way it is very easy to remove it when needed.
The last time I installed the program was in May of this year and it was on Debian 12 KDE 5.xx. Most likely also on X11 so I can’t tell if it runs on Wayland. But since you use a program which runs on KDE 5.xx, using it on 6 might be problematic.
I get a feeling that at CEWE they want to have a Linux version but it is not highly maintained and is sometimes far behind reality. I had that with a library some years ago which I had to look for on the internet (and found in the Debian archive) and now KDE 5 and 6. Such a shame because it is a great program with which you can make fantastic albums, but as it normally is: only the largest group of customers (Windows users) is served well.
I hope you get it running the way you want it, but to be honest I have my doubts. You can however reboot into X11 and use it and when ready reboot again in Wayland. Not great but what can you do?
Quite possibly, though I have to wonder whether they use QT for other platforms, which might offer some hope for the future.
When I am processing images, I generally do it in X11 anyway, given that Wayland currently has no colour management.
The one thing I have done is email CEWE and thanked them for the Linux version. There is a British saying, “You catch more flies with honey than with vinegar”, so a bit of praise can’t do any harm.