There's a feature that allows you to try and target a specific VMAF score, but it doesn't work very well. What av1an does do for you is increase the speed by a lot, especially for aomenc and rav1e, which don't scale well with high thread counts. SVT-AV1 doesn't really have this problem.
A faster encode might allow using a slower speed/preset setting, which would increase quality per bitrate a little bit. But I don't really consider av1an a tool that increases encode quality, to be honest.
A faster encode might allow using a slower speed/preset setting, which would increase quality per bitrate a little bit. But I don't really consider av1an a tool that increases encode quality, to be honest.