Hm, I don't really see where the link would be, the v30 release didn't change anything that should affect this. I do a lot of tests myself between versions (regularly testing Beam with OBS 30 since the first beta of it) and didn't observe any changes in bandwidth consumption.Since the release of the latest version of OBS 30.0.0, xObsBeam consumes a lot of network bandwidth.
Maybe the update somehow has changed your compression settings? That influences the necessary network bandwidth a lot, and of course video settings in OBS like resolution and frame rate. You can always drop a link to a log here (Help -> Log Files -> Upload Current Log File), then I can see your settings and compare that to expected bandwidth needs.