Serious question: can you point out some serious complaints? They seem to have an exhaustive justification for their reasons to only support Pixels, see https://grapheneos.org/faq#future-devices
This list always bugged me. If Pixel - for example - starts to introduce security patches slower, they will change this list... or even ignore it. If something more secure comes into the picture, they will change this list, and they will ditch supporting Pixel. If they don't, then it will be quite obvious, that they formed this list only to meet only Pixel's feature list. Also Google can obviously satisfy this list more easily, than any other company, so basically they created a moot for them.
This list always bugged me. If Pixel - for example - starts to introduce security patches slower, they will change this list... or even ignore it. If something more secure comes into the picture, they will change this list, and they will ditch supporting Pixel. If they don't, then it will be quite obvious, that they formed this list only to meet only Pixel's feature list. Also Google can obviously satisfy this list more easily, than any other company, so basically they created a moot for them.