I think you don’t understand.
You can write CloudWatch metric math in CloudWatch console - that “e1 series”.
You can write exactly the same CloudWatch metric math in Grafana queries - you have different UI, but it will be the same.
Please study this SLO - IMHO exactly your case, I don’t use generic m1,m2,e1 IDs, but more meaningful names in IDs:
Use doc to understand used CloudWatch metric math functions, operators, …, e.g. FILL: