Depends on how hard you’re willing to work and if dropping a unit will affect anything. If you drop a unit and you don’t bother to use the extra time to work harder on the remaining units, then there’s no point in doing that. Also, double check the number of units required for transfer, any scholarships you have currently and if it’ll impact your course map (if your intent is to also have minimal impact on graduation), because there may be a condition stating that you must be doing X amount of units to transfer or keep scholarships.
(This is especially the case if you’re doing three units currently, as dropping to one or two units makes you a part time student and the condition is usually that you have to be a full time student on scholarships.)
Pretty sure Monash extended their census date due to the coronavirus situation, but I’d also double that so that you know if you’ll have to pay for the unit you’re hoping to drop. (If the census date has passed, it might be easier and less costly to simply keep the unit you want to drop and work on all units as normal.)
If possible, I’d probably call Monash Connect or your faculty’s student services when they’re open (seeing as you’re unlikely to be able to visit them in person) and asking for their advice as well.