I Own Amazon Niche Blogs and I use some custom CSS to design the Blog Posts for good conversions. But, the css look bad on AMP. So, I removed AMP.
The AMP Pages were deindexed within a day. Haven’t lost any Traffic.
The time Spend on Mobile Page also increased.
Also, I recently switched from NewsPaper them to Genesis (Aspire Pro theme). The Site Speed is good now.