I've been experimenting with AV1 using FFmpeg with SVT-AV1 for 2 years. I've encoded quite a lot of my videos in AV1 by now, mostly just animated content.
AV1 is really good for an open source project, no doubt about that. But after so long using it, I can safely say that it is really just good for storage saving with excellent quality-speed tradeoff, however, it lacks fidelity. My major discontent with AV1 has been how the encoder blurs some details completely out even when setting crf as low as 14 whereas HEVC doesn't at all.
Edit: Also in some instances, particularly with non-animated videos, AV1 performed way worse than HEVC which I believe is due to it doing a poor job in varied and difficult scenes.
At first, I thought AV1 is only better for animated videos but later I found its really just any video so I've switched back to using HEVC for storage and decided to use AV1 only with preset 6 and fast decode on for mobile devices.
I don't mean to say that AV1 is bad, it does provide better quality than HEVC for sure but I wouldn't call that an upgrade when HEVC still has the major edge in fidelity.
It makes sense for VOD services to make use of it but personally, I wouldn't use it for anything except quick and super low bitrate encoding.... for now.
For what it's worth, I personally think svt-av1 also produces a worse looking picture than aomenc. I'm not personally convinced that AV1 is at fault, just that the x265 encoder is much more mature than svt-av1, aomenc, and rav1e. I haven't tried a high quality film source yet, mostly just SD animated things, where svt-av1 usually loses to aomenc in what I'm looking for (best quality picture per bitrate), but svtav1 tends to win out in encode speed.
If you haven't tried it out yet, I would suggest trying av1an (an encoding framework) with aom and at least comparing a few samples with what you get out of ffmpeg and svt-av1. Av1an can do chunked encoding, which helps speed by running multiple encoders in parallel. I don't think that aspect helps much with svt-av1, but it does seem to help with aomenc.
I wrote a bit about it here (https://lemmy.ml/post/2843230), though I didn't include any film grain settings in that post.
For me, they both lose details the same way, AOM is just higher quality and compresses even better, neither of which is feasible for personal use at this time. I have some hope for rav1e but it is not mature enough and also missing many features, so not using that either.
The suggestions in this document may be of interest to you if you are willing to give aomenc one last look. And as for using it with ffmpeg, aomenc benefits from a two pass encode (which av1an will do automatically) https://gist.github.com/shssoichiro/a46ff01db70243c1719479f6518ea34d