I think emphasis needs to be made on two points:
A. The degree of curvature.
B. The location.
I have a slight (maybe 10-15 degree) upward curve at the base of my dick and I’ve never had a problem in regards to sexual positions. I neither like it or dislike it.
Although I can understand if you had a fairly extreme curve in an awkward spot (ie. 30+ degree curve one inch behind the glans) then it would be difficult for a lot of positions.
There is a loss of length. Take a piece of string and bend it, the empirical length is reduced, assuming that bend cannot be straightened (as it cannot with a raging boner)
A 6” piece of string in any shape is still 6” long.
I'm a big fan of 50 Cent, or as we call him in Zimbabwe, four hundred million dollars.