As I wait for human answers, I post as a "first approximation" ;-) the answer of GPT-4.1 nano:

Great question! You're essentially considering batching multiple animations to reduce the number of `requestAnimationFrame` calls, which is a common performance optimization technique.

Key points to consider:

1. Performance of `requestAnimationFrame` :

• Browsers are optimized for `requestAnimationFrame` and typically handle a handful of calls per frame efficiently.
• However, calling `requestAnimationFrame` thousands of times per second (once per each element) can introduce overhead, especially if each callback does significant work.

2. Batching Animations:

• By grouping multiple element updates into a single `requestAnimationFrame` callback, you can significantly reduce the number of frame callbacks, which can improve overall performance.
• Inside that single frame callback, you'd iterate over all elements, updating their positions accordingly.

3. Trade-offs:

• Complexity: Your implementation becomes more complex since you need to maintain a queue of pending animations, manage their states, and execute all updates together.
• Synchronization: You need to ensure that all animations are synchronized within the same frame, which might require additional logic for timing and easing.
• Flexibility: You may lose some granularity or control over individual animations if not managed carefully.

4. Browser Efficiency:

• Chrome, Firefox, Safari, and their mobile variants are quite optimized for `requestAnimationFrame`. They can handle multiple callbacks per frame efficiently.
• But reducing the total number of `requestAnimationFrame` calls can still be beneficial, especially when dealing with hundreds of simultaneous animations.

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### My recommendation (based on experience and best practices):

- If performance is critical (e.g., hundreds of concurrent animations):
Implement a batching system that consolidates multiple move operations into a single animation frame callback. This is a proven optimization strategy, especially if each animation is relatively simple.

- If simplicity and maintainability are more important:
Your current per-element approach is straightforward and easier to manage. Modern browsers handle this well for a moderate number of animations.

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### Summary:
- Yes, batching `requestAnimationFrame` calls can improve performance when many animations run simultaneously.
- You don't need to test across browsers for the basic principle—most modern browsers are quite efficient with `requestAnimationFrame`.
- Implementing a batching system involves extra logic but can be worthwhile if performance issues arise.