I used buttons for the Odin 2 Mini from SakuraRetroModding on Etsy. They fit without any modifications, except that the original buttons are glued to the membrane. Thankfully, it's easy to unglue them by cutting through the glue with nails.
Here is how the unglue process looks like. The video is for RP5, but the approach is the same for the Mini.
The new buttons are quieter, have a lower profile, and feel similar to an Xbox controller overall. I'm really happy with the mod!
It's awesome! My only complaint was buttons - they feel awful without the mod.
Personally, I'm satisfied with the screen size. I think people usually complain about the screen-to-size ratio, but it's because of the bezel-less design. Here is a side by side comparison with Anbernic 406h:
And here edited with "bezels":
These pictures aren’t mine; they were shared in the Retroid Discord.