Installing a bathroom ventilation fan

Not sure where this question belongs
I am adding a 3/4 bath to the upper level of our 1930 story and a half.
I now have to look at installing a vent fan and looking for suggestions as I have very little room to work with.
In the upper level I have about 19 inches of level ceiling before the ceiling begins to slope down, the roof has a ~10:12 pitch.
So the idea is to put a vent fan in the level portion and vent to the outside, i guess I would cut a hole for the fan itself, then I am probably going to have to cut another hole to route and run a vent to the outside. I think it would be pretty difficult to do it all through the hole cut for the vent fan. Although I could cut the sheetrock out completely between the joists and patch as necessary
I am looking for suggestions and even recommendations on technique as well as the best fan for this type of situation.

How easy it it to secure the flexible duct to the roof vent and then slide the vent up under the shingles and secure it without messing up the duct.
Then I could probably connect to the fan frame and install the frame to the joist. I would still need a larger hole so i could angle the frame upo in there but I can always patch as necesary.
I have no attic access so working through one opening can be difficult.
Thanks for any suggestions