/amp/ vs ?amp=1 caching

I have a website with AMP support for mobile and WP Super Cache.
No problem on desktop with the message:

<!-- Dynamic page generated in 0.486 seconds. -->
<!-- Cached page generated by WP-Super-Cache on 2021-09-21 16:07:25 -->

<!-- Compression = gzip -->

But on mobile and AMP pages I just get the following:

<!-- Performance optimized by Redis Object Cache. Learn more: https://wprediscache.com
Retrieved 23047 objects (2 MB) from Redis using PhpRedis (v5.3.4). -->

So it’s not working on mobile as expected. The site is responsive, but I have enabled Mobile device support as I’m using the wp_is_mobile function.

So far I use pages AMP page ending with ?amp=1 like https://www.cnx-software.com/2021/09/21/opencv-ai-kit-lite-a-compact-4k-tri-camera-kit-for-computer-vision-applications/?amp=1

I prefer it that way, because if a mobile user shares the page, a desktop user will still see the desktop page. The downside is the time to first byte is longer due to the large of caching and Google Search Console reports my mobile website “needs improvement”.

However, if I change the URL structure to use /amp/ instead, for example, https://www.cnx-software.com/2021/09/21/opencv-ai-kit-lite-a-compact-4k-tri-camera-kit-for-computer-vision-applications/amp/ caching works fine, and the mobile website speed is good, but the downside is that desktop visitors would be served the AMP page, and it may break the site in the future.

So I’d prefer using ?amp=1 with WP Super Cache generating cached pages for it, but I have not found a way to implement this yet. Is there any solution?