A Generic System Image (GSI) of Project Treble is not a full-fledged replacement for stock Android ROM or a device-specific custom ROM, such as iodéOS, but - it is an excellent basis for interested users to get to know the special custom ROM (iodéOS), primarily for Android smartphones and tablets that support Project Treble (from Android 8.1, better Android 9.0 or higher) but not from device-specific iodéOS ROMs.
Google itself releases GSI images, currently official even for Android 12 experimental. The most prominent GSI ROM maintainers are GSI-Guru Pierre-Hugues HUSSON aka Phhusson (AOSP) and the phenomenal Andy Yan (LineageOS 18.1), but other luminaries also offer good software.
I myself like to work with /e/OS GSI images. Currently, I was able to degoogle a Gigaset GX290 (outdoor smartphone) and a Samsung Galaxy Tab A7 10.4 (2020) SM-T500 WiFi based on Android Q vs. /e/OS-Q. The next attempt will be to equip the Galaxy Tab A7 10.4 ‘gta4lwifi’ based on stock Android R with a Signature Spoofing ‘ready’ GSI ROM and the Minimal microG NoGoolag Edition, as I’ve already managed to do with a Samsung Galaxy Tab A 10.5 (2018) version SM-T590 (Wi-Fi).
Long story short and question to the iodé team:
Will there be Generic System Images (GSI) of iodéOS 1.x and/or 2.x for the architectures arm - arm64 - binder sooner or later? I would prefer it to all other GSI ROMs.