Sorry for this bad situation! Please hold “Volume +” when booting. A menu will come up. Use “Volume +” to move the hilighted selection, and when on “Recovery” then press “Volume -” to boot into recovery.
Assuming that works, in recovery you can select “Factory reset” as a first attempt.
If that is how you did it before with no success, then you may need to manually install the latest image. It is easy for you to do that with adb sideload from recovery, but that means you need to have adb installed, not sure if you are Windows or Linux (or macOS).
If you are familiar with adb, then get the system download here. in Recovery you just select “Apply update” then use this command: adb sideload iode-6.6-20250729-brax3-ota.zip
Now, if this still fails, then you will need fastboot or SP Flash and follow this guide: How to manually install or update your OS on your BraX3
Sorry if all this is above your paygrade (this isn’t for everyone), maybe Brax will have you ship back the device and they fix it for you. You would have to contact their support.