I have no idea that the GA plugin can have an influence on the cache function. GA is Javascript based, but you need an HTTP header generated by PHP to influence the cache behavior. Javascript cannot send HTTP headers because it runs in the browser and not on the server. The fact is that if I activate the ad blocker for your site, the caching works. Therefore, logic says that the malfunction is caused by your server or some PHP based function. However, I don't know your installed extensions for GA or GDPR, but that's irrelevant because according to the logic only headers can set what can also set headers. Javascript cannot set headers!