Oh for sure, i'm just saying a 3.5kg one is on the upper end of usable. I've used one a good bit lighter than that and one slightly heavier and the heavy one was a BEAST to maneuver.
This one is under 2kg for example: https://sigiforge.com/products/sigi-montante/
Regenyei sells one aka "The Beast" at 3.6kg as their heaviest offer: https://regenyei.com/product/two-handed-sword-01/

Once you go past that it gets so difficult to weild effectively - depending on your weight, strength and size of course.