On my 2019 MBP, the thank-you frame transition is choppy in Firefox and very choppy in Safari. In my brief attempt to use the browsers' performance profilers, i

On my 2019 MBP, the thank-you frame transition is choppy in Firefox and very choppy in Safari. In my brief attempt to use the browsers' performance profilers, it looks like 40ms per paint in Firefox and 300ms per paint in Safari. Chrome is less than 2ms per paint and only drops about 20% of rendered frames. Can anyone with more browser perf debugging experience explain why this animation is so janky, especially on non-Chrome browsers?