Evening (or morning, afternoon), thanks for reading:
I recently installed 3.3.1 and sliced with the profile imported from my 3.2.1 version - I don't believe anything changed, though I did pour over all the settings and nothing is standing out as an obvious cause of this problem: the outer and inner walls of my prints occur at my normal, expected rate (60mm/s). However, the infill and supports print at something approaching 1 or 2 mm/s. In Cura, my slowest print speed is reading at 30mm/s.
This issue persists between printers and slicing different files with 3.3.1; files sliced