Sorry for the wall of text, but as we put it all down, we realised that we had to add more and more criteria.
We are planning our last trip for this year and are based in Germany. Our plans/funds unfortunately don't allow something as far away as Scotland/Sweden/... so we are looking in Germany, Denmark, BeNeLux, Western France, Austria or Switzerland.
Ideally, this trail is not too much of a misery in autumn. We are fine with lots of ups and down, but not equipped for mountains or very alpine terrain in this time of the year.
We would be fine with huts or shelters, but could also wild camp (if it's no too much of a hassle). Doing just a certain section (5days max) would be fine for us as well.
Bonus points for remoteness and beautiful nature. Walking along roads, forestry roads or villages all day is a bit monotone after a while.
Might be that this does not exist; we enjoyed e.g. the West Highland Way very much and are looking forward for Sweden/Norway.