fix: Improved loading jank fix, new DelayedMount component

app/components/DelayedMount.js

@@ -0,0 +1,24 @@
+// @flow
+import * as React from "react";
+
+type Props = {
+  delay?: number,
+  children: React.Node,
+};
+
+export default function DelayedMount({ delay = 150, children }: Props) {
+  const [isShowing, setShowing] = React.useState(false);
+
+  React.useEffect(() => {
+    const timeout = setTimeout(() => setShowing(true), delay);
+    return () => {
+      clearTimeout(timeout);
+    };
+  }, []);
+
+  if (!isShowing) {
+    return null;
+  }
+
+  return children;
+}