Bootloop after installing V0.21 on preinstalled /e/ S9

what to do now…

Watch and wait, I think.

The way that developers are made aware of these issues is when someone tells them. We do this in this way https://doc.e.foundation/support-topics/report-an-issue, (new users might possibly face a login issue which is fixed by sending exact details of the failing login to support@e.email)

Following the link I gave you above, takes you to the issue raised there

https://gitlab.e.foundation/e/backlog/-/issues/4855#note_163070

If you add to that please be careful to show where your situation is the same, but particularly where it is different (in that I think you downgraded to Oreo).

You will know that you can demonstrate whether you have “Oreo | Q” and also “stable | dev” from

Settings > About phone > Android version > /e/ version.

It is reported by others that this does not work on every Samsung, but if you long press on /e/ version you should be able to “Copy to clipboard”

To stay up to date, read posts like OS Upgrade - S9 / S9+ found under development-updates and follow the posts in hashtag ota-upgrade