How to enable chromium based hardware acceleration on early 2013 macbook?

So got the above macbook and dual booted Ubuntu. I've been trying to enable hardware acceleration on vivaldi. Followed these instructions and after some tweaking seem to have it working. But video is still choppy. Apparently I have 2 GPUs on this thing, and vivaldi is using the nvidia gpu, whereas macOS uses intel. The video plays smoothly in macOS. Trying to figure out if a) there's a way to force/choose the GPU through vivaldi somehow, OR b) if the issue is on the ubuntu end, preferentially using the nvidia driver for hardware acceleration. I'm using the following flags at startup:

vivaldi-stable --use-gl=desktop --enable-features=VaapiVideoDecoder --ignore-gpu-blocklist --enable-gpu-rasterization --enable-zero-copy