The broader you can make your knowledge and skillset, the better value you will be able to provide your customers. If I were in your shoes, I would probably look at the SAP certifications to gain the knowledge of the application of the product if not the product specifics. In other words, learn what the solution is used for and understand the application of the solution. The product specifics will only be gravy and improve your ability to support it for your current organization.
The best way to be successful is to do something that you like doing. If you find SAP boring than SAP isn’t the right career choice for you. If you like databases stick with it. SQL Server can be a very rewarding career if you love it, and are very good at it.