I am new to Premiere but am not impressed to find that the VBR encoding setting under Bitrate settings seems to vary wildly for bizzarre reasons, in some cases more than tripling the output file sizes.
I had a project that initially output at 25 Mbps using VBR, 1 pass. When I applied a single razor cut, splitting the video into two segments, the output setting jumped to 76 Mbps. This was exactly the same project using exactly the same video source file. The only difference was that I had applied a single cut to the video. The output size of the video jumped from 3 Gb to over 9 Gb. The video had been recorded on an iPhone and I had left the export settings as Match Source - Adaptive High Bitrate. I also had problems dealing with blown out video with all the highlights whited out until I found a workaround involving an input LUT called HDR CONVERSION LUT and colour space override Rec. 2020. It is frustrating that Premiere doesn't seem to be anywhere near as intuitive as programs such as InDesign.