I'm retired, I'd take my time.
First of all - did you trim everything on the upside? Or did it grow that way.
I'd start at the top with chainsaw and pole saw. Cut a bunch away, haul it off, repeat. Keeping a clear path in case it moves. Trimming the branches back to clear 5' or so of stem at a time, then cutting off that part. And might put a good stout rope "down trunk" so if it stands up it would help cutting down more pieces.
If it "stands up" during the process I could easily get out of the way, then cut it at the base and have a rope to assist.
Take lots of picture or videos please.