I suppose it depends on what exactly you are looking for in charts. But most cases are covered out of the box.
The above is an automatically generated chart I got from clicking on “Analyze All” from one of the cards on the Properties tab of the Overview page. I had to do absolutely nothing to create that chart beyond clicking the button. It’s using the default rrd4j with the default persistence strategy. Note that it’s charting two different types of values, in this case VOC in ppm and Radon in Bq/m3 and charting was smart enough to create two Y axis, one for each.
I cannot stress strongly enough that all “newbs” should first read the Concepts sections of the docs followed by the Getting Started Tutorial. Much of what you discuss above is also covered in those docs.
There is a whole page dedicated to the semantic model in Getting Started here and the page in Getting Started for the Overview Page further describes how it’s built from the semantic model and how to customize it.
For more information than you need about the semantic mode, see A Deep Dive into the Semantic Model.