SQL Database writes suddenly slow.

Writing to SQL Server Database has suddenly become very slow since April 26th 2025.

Everything is run on premise within the same region. Nothing has changed on our end.

Writing tasks that once took 11 seconds now take 3 minutes.

Writing tasks that once took 10 minutes now take 9 hours!

Have tried to scale the instance up, but I still achieve exactly the same performance.

DTU doesn't pass 25% either. So I don't think instance type is the issue.

What can be the cause of this?