Have you looked at these threads for the DJI app issue?
https://discuss.grapheneos.org/d/904-grapheneos-pixel-6-dji-fly-app-compatibility
https://github.com/GrapheneOS/os-issue-tracker/issues/2527
As for Instagram...ugh. Absolutely insane to use Instagram for private communications, but I get it, you can't change your whole social circle. What you can do is isolate Instagram and similarly untrustworthy apps into a second user profile in Android, so at least it won't have access to your real photos, contacts, etc. I use Shelter for this purpose, but there are other options as well.