Created attachment 355195 [details] Testcase. See the attachment. The pseudo-element is out of flow, so it shouldn't affect capitalization. So expected rendering is "Homeblog" instead of "HomeBlog". Furthermore, removing the pseudo-element dynamically doesn't fix the issue, and you need to force text-layout again somehow to see the correct rendering.
Chrome and Safari match behavior here (in 2022). Firefox produces the 'expected' beavhior. Is there a WPT covering this behavior? Please REOPEN this bug if a Web Platform Test illustrates an issue. For now, we should match Chrome behavior to avoid Website Compatibility issues.
This is covered by https://wpt.fyi/results/css/css-text/text-transform/text-transform-capitalize-033.html