My biggest concern is the life cycle of the device. I almost went with Motorola for my last phone, but saw that you were lucky to get 3 years of OS updates. Is that likely to be better on GrapheneOS? If so, that is a huge win imo. If not, it still isn’t ideal because I don’t want to have to buy a new phone every 2 years…

Thats the trick, when a company supports romming, you can extend the support for however long you want!