When you say “I work with a SQLserver database”, do you mean that this is the
one you know best and generally interact with (quite independently of anything
to do with Grafana), or do you mean that the data you want to visualise in
Grafana is stored in a SQLserver database?
My answer to “which data source should you use” is more based on “what sort of
data do you need to store and visualise” and “where is that data coming from”
than it is based on what you may happen to be most familiar with.
Many people using Grafana can and do quite reasonably treat the data store as
a “black box” which data goes into from whatever source is generating it, and
which Grafana uses to display the graphs on its dashboards, but the details of
what happens in between are really not important.
So, what data do you want to work with and where is that coming from?
Once we know that, some people might be able to advise you on configurations
they’ve used for similar stuff in their own projects.