Low bitrate even when exporting with High quality on 720p display

Hello. Even when exporting at high quality, the final video’s bitrate seems to be low.

Hosaka recording:

vs. OBS output (directly uploaded OBS mkv to YouTube):

I know youtube does some video processing too but even when viewing the exported video locally, it has artifacts. My display resolution is 1366×768. Attached logs as well.

There’s this log in particular about the app using CPU encoding:

10:45:47.410 WARNING hosaka.core.ffmpeg:190 - VAAPI runtime probe failed. AMD GPU detected - ensure 'mesa-va-drivers' is installed. Falling back to CPU encoding.

Might that be causing the issue, or is it ffmpeg settings? I did try fixing it yesterday but couldn’t find a way.