These photos might give you a hint. My case is off brand. I will be moving to another district next month and will remove the gpu before travelling.What is your case, and what is the orientation of your graphics card.
In a traditional case, yes a heavy card can sag.
If you think that might be a problem, there are brackets to adress the issue.
Normally if theoutput end is well tightened to the case, there will not be much of an issue. So long as the pc is not regularly moved.
Depending on your able management and the length of cables you might have from the PSU, you could use that to prop the GPUup, somewhat, but I'd look into a GPU support bracket for that GPU only and only if the card's sagging to a level you're not comfortable with.