I don't believe most countries hold judges accountable for bad ruling at all even before AI era.
"Check and balance, except judiciary."
It wasn't just a bad ruling. It was judicial misconduct.
In the US, local/state judges often are elected (probably varies by state). Federal judges can be impeached.
In the UK lower court judges are sometimes removed for misconduct.
Only the king (at the petition of parliament) can remove a high court or appeal court judge, and that's only ever happened once, in 1830.