Adding the desired classes and rules to the td elements is the way to go. Here's one example that we have in a KB article: https://docs.telerik.com/blazor-ui/knowledge-base/grid-conditional-cell-background.
If you don't need the rows colors to be dependent on the row data, you can simply inspect the classes and rules we have out-of-the-box, and add heavier selectors with the rules you want. This blog post can help you in doing that: https://www.telerik.com/blogs/improve-your-debugging-skills-with-chrome-devtools.
UI for Blazor