I have a tubing cutter with a deep blade I bought online, problem with it is seems to distort the roundness of the pipe, it does make clean straight cuts. I saw this tool online that is used to press the pipe into the fitting but I don't know how that would work in the ceiling , probably one of those things you need to use on a bench.
I had a Home Depot one that broke on one side and then cut straight. But it finally crapped out. I tried to break my other one in the same place without the same results. I only use them for up to 1 1/4. Everthing else is cut with a saw saw.
You need to put the phone down and get back to work!
I've used my DeWalt miter saw on some bigger plumbing jobs. Works great, but I don't think I want to lug it to the basement for a half dozen cuts for a vent and Combustion air piping. The tubing cutter works good, it is a different wheel and is slow. Sawzall or PVC saw and a couple twist of the reamer, deburrer works for me.
If you've got power then cheat - get a chop saw cheap somewhere! Always cuts straight and fast.
When I don't have power I wrap paper around the pipe so its edges are flush then use a felt/pen to mark the circle. From there cut on the line (but not through the pipe) only on the side facing you and rotate the pipe to cut some more. usually takes me three or four complete rotations of the pipe before I cut all the way through. You get a very straight cut this way.
Learned that from a plumber when we were installing 8" Sched 80 for a public pool circulation system. If you do it a lot then instead of paper you can get a special roll of impregnated/marked material from a plumbing supplier thats specifically for marking cuts around pipe.