You will find that by using 'Trim to Roof', the wall will be trimmed by the 'Trimming Body' of the roof (you can turn this on in on screen view options to see the trimming body).
You can set your roof trimming body to the roof contour rather than the pivot lines.
This will extend the trimming body to the outside edge of your roof in your case.
Or the other option is to use Solid Element Operations to trim the walls.
This will not use the trimming body.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11