I am now sharing all my decorating ideas with DH for our soon to be retreat, in our rather ugly unfinished basement, lol.
Oh my. You have stepped over the edge. The slope is slippery. Enjoy the ride

You should consider keeping the horizontal run as short as possible, double wall connector pipe and 2, 45* elbows to complete your 90. Basement installs with long horizontal runs = potentially frustrating smoky start ups/reloads until draft gets established. The horizontal run will also need to run uphill. I believe 1/4" per foot is acceptable. Hopefully others will chime in on these issues.
Menards carries the double wall required.