Honestly, I think you summed up the biggest issues. As much as I look forward to getting a Pixel for my next phone solely for GrapheneOS, it’s understandable for people looking to degoogle to not want to buy a Google phone. The developer I think is the bigger issue. Despite having since stepped down, his behavior went unchecked for long enough to make quite a bad reputation and leave a bad taste in a lot of people’s mouths. While recovering from that will simply take time, I have wondered why they haven’t taken the opportunity to come out with a Graphene-lite for non-Pixels. Something like CarbonOS as secure as possible sans Google hardware. Could easily overtake Calyx/Lineage.
What email provider are you moving to?