I agree about keeping the pipe inside to benefit from the radiated heat thus avoiding excess creosote build up (an outside pipe will do that). You can make an attractive heat shield to help keep the pipe closer to your inside wall. I prefer a heat shield which will cover a big section of the wall rather than an angled heat shield following the pipe.
There are amazing designs for the heat shield to make it attractive as well as creating a natural draft to move even more heat from the heat shield up into the room. The best design I’ve seen here in Montana had a 3 1/2 inch air gap behind a layer of
concrete wall board. The board was overlayed with thin-set then small, dark and colored river rock created a leaping trout design. All around the trout, lighter colored river rock and quartz created a river effect like
water. I can see you creating two focus points with the pipe angling between them. This will then help the pipe look like a natural element within the heat shield.
This heat shield met the floor yet six inch intended vent holes existed the entire perimeter with one longer rock sitting sideways between each vent. All those vents allowed for cool air to enter at floor level then gradually warm as it would rise. A gentle airflow could be felt after the rocks were all warmed sufficiently.