The need for lots of focuser travel mostly boils down to two things: (1) you are using the SCT also for terrestrial work, or (2) you are also doing visual work, and your camera and eyepieces are not parfocal.
There is not much you can do about case (1), but you should do something about case (2).
Even without a reducer, an SCT is a compound system and the backfocus matters even though you can force the system to focus by severely changing the distance between the main mirror and the corrector plate.
If the back focus is not precise, stars at the edge of the image circle will exhibit either radial patterns (too short a back focus) or small circular arcs (too long a back focus). You might be able to get the middle of the FOV to come into focus, but the edges and corners of your image will still not be right if the back focus is wrong.
When you have the correct back focus, your camera should be mostly parfocal with an eyepiece on a star diagonal that the same manufacturer sells, and there should (:-) be no need to have extreme focuser travel.
My recent exchange in this forum reminded me of parfocal vs backfocus (I only have an old Meade SCT and a small Celestron SCT, neither of which I use often, so something like that didn't immediately come to mind): https://bbs.astronomy-imaging-camera.com/d/12961-asi462mc-and-focus-with-edge-8-asiair-pro . The OP of that thread had his backfocus mistakenly set 30mm to 40mm too short, and could not attain sufficient EAF travel to focus when his eyepiece was in focus. Setting the correct backfocus apparently fixed the need for large EAF travel (and probably vastly improves his star images at the edge of the image circle too).
Chen
