Possible to restore SeedVault backup to different ROM?

When iOS support ends for my iPhone, I would like to replace it with a Pixel phone and go with GrapheneOS. But I am wondering: (How) can I transfer my contacts, photos etc.? (without proprietary cloud solutions) It looks like there's the possibility to [transfer those data by Lightning2USB-C cable](https://support.google.com/pixelphone/answer/7129740?hl=en#zippy=%2Ccopy-data-from-your-old-phone-with-a-cable-recommended) . But this only works on StockROM and LineageOS, right? Not on GrapheneOS!? My idea was to buy the phone, flash Lineage (with GApps) on it, transfer the data from my iPhone, perform a SeedVault backup on an external drive, flash GrapheneOS and restore that backup on the device. Would this work? Has anyone tried? My two main uncertainties: 1. Does the cable transfer from iOS work with LineageOS? 1. Does restoring SeedVault backup between ROMs (Lineage, Calyx, Graphene etc.) work?