I’ve tried installing the GSI and documented what was necessary in this thread in case anybody else wants to attempt it, too.
While I was able to get it to boot into the UI, it is not anywhere close to being usable in practice.
The UI is incredibly glitchy and laggy and I was only able to go through the initial setup process with several reboots. The lock screen is fully transparent with only the text shadows showing, the Bliss launcher hangs a lot for no clear reason, WIFI cannot be enabled (though the documentation for the abandoned unofficial LineageOS build mentioned earlier in this thread says “If WiFi doesn’t work, try flashing custom kernel”, so there are likely ways to fix it).
The cruel thing is that when it works, it works very well and it’s infinitely more snappy than MIUI, all default apps like Settings, Browser, Mail, etc. open fine and respond instantly – when they do. The camera works, too, but launching the camera app and taking a photo causes another multitude of hangs.
It’s a real shame since it works well enough to make it painfully obvious how well /e/ could work on this device. If we had official support, that phone could be used for many more years, and not only that, it would be much better than it ever was with the original ROM.
I keep my fingers crossed that we’ll see an official version one day.