This answer already addresses that Ultimaker Cura "eats up" platform space for e.g. skirt, brim, raft, dual extruder, deposition of priming blob, prime towers, etc. Disabling those features will reclaim platform space so you can print larger prints. However, that will only work when your printer is correctly configured! E.g. the center of the bed needs to be the center of the center in the slicer which needs to have the specific sizes of the bed dimensions. Note that increasing the bed size past the actual dimensions is not considered to be a nice solution, it is an easy work-around that gives you extra space in X+ and Y+, i.e. it does not center this newly created space, furthermore, this can destroy your printer is there is tight space left on those axes! Let's illustrate that with an example, if you have a 200x200 mm build plate and want to slice something of size 200x200 mm, this should be centered around (100, 100), if you change the bed size to 220x220 mm, Ultimaker Cura will center the print around (110, 110) which means that the print maximum coordinates are 210 mm; this is outside the bed area and potentially can destroy your printer!
What you should check is if the physical center of your bed actually is the center as defined by the firmware of the printer (surprisingly, many of the cheaper printer have this incorrectly configured). The answers on question "How to center my prints on the build platform?" (Re-calibrate homing offset) describe how you could do that.