I'd expect the installer to support more devices over time, since /e/ officially supports 269 devices:

https://support.e.foundation/devices

It's promising that more and more alternative Android distributions are offering installers to make them more accessible to average phone users. On the Linux phone side, even Ubuntu Touch has an installer that supports 81 devices: https://devices.ubuntu-touch.io/installer/

But, device manufacturers need to make bootloaders unlockable for these installers to work, and I agree that regulation is a practical way to make this happen. I can see Europe taking the lead on this with the goal of reducing e-waste by encouraging the reuse of old devices.