Edge DevTools Canary can now show you detailed stats on your CSS selectors when a style recalculation occurred. You just need to check the "Enable advanced rendering implementation" option and select a "Recalculate Styles" block.
Explainer - https://github.com/MicrosoftEdge/DevTools/blob/main/explainers/StyleTracing/explainer.md
Interested in Rendering Patterns for the web? https://bit.ly/renderng: our refreshed patterns.dev guide covers Static rendering to Streaming Server-Side Rendering w/great visuals by Lydia Hallie.