Hi, Leo!
What is odd that the same ads do not cause any problems on mobile but they do on AMP although I am not sure if the problem is really because of the ads.
Could you please check what causes the layout shift on AMP while there is no problem on normal mobile pages?
where are you seeing the Layout Shift? I ran a Page Speed Insights report and Lab Data CLS is 0. I then ran a performance test in Chrome Dev tools and no CLS is visible or reported.
Aah you mean horizontal scroll… you would need to check the advert settings you’re loading to correct that. Nothing that the Theme can do can change that