Sure. According to the way Veeam calculates it yes. But the VSAN is not really pushed that hard during backups. We have two proxies, processing 4 VMDK's in parallel ( 8 in all ).
My point is: there will always be "the slowest component dragging things down".
I'm perfectly satisfied with our system and in my mind, ignore that "negative information" I get fed every day.
This topic is as old as the day when Veeam introduced the "bottleneck display feature". People have been "worrying over nothing" ever since (well, not always, folks with performance issues have valid things to worry about).
This feature, though meant with the best intentions, has a "dark side" too