SSRS developer new to Power BI

Hi all. I'm a noob to Power BI and have been building SSRS local reports for some years (the ones invoked from C# code and not on a reporting server). I'm playing with Power BI to try to create something similar to what I've done in SSRS; however, it's been a challenge. 

I'm used to Tablix controls and subreports, being able to have very fine-grained control on everything via expressions written in VBA. Controls/columns/rows can be shown/hidden. In SSRS, I can feed a report a dataset of my own custom C# objects as a list. Everything can be right-clicked and manipulated. In my current job, I write reports that are fired off from C# based on criteria and the user then sees a PDF -- lots of tabular data but some subreports with just strsight text from the db. 

From what I'm seeing in Power BI, this level of flexibility doesn't seem possible. Am I correct? I'm liking many things about Power BI but am skeptical it replaces SSRS. Please enlighten me and help me see the light! I'm also open to tutorials for us SSRS devs that can ease us into Power BI. 

Thanks.