Yes, it's "relatively" easy. They had over-the-air delta updates with Android 10, but not for 11. Here my current steps for each ROM upgrade. Installation would be similar:
- Connect USB
- Boot in Fastboot: Press and hold Volume Down, then press and hold Power
- Install TWRP recovery `fastboot flash boot twrp-...`
- Select to boot recovery mode using Volume Up/Down
- Format system and cache partitions ONLY. Leave data and internal
- Choose Advanced > Sideload, then run `adb sideload PixelExp...zip` on computer
> AOSP updates via Pixel Experience ROM
I'd be interested to know what this is! Is it something I can use?
Edit: Found it now - looks interesting. Was the installation relatively pain free?