Just upgraded to Craft 3.5+ the pages are cached (instant load on a 2nd run) but the templatecaches and similar tables are empty. How exactly does it work now? How do I flush cache for 1 specific page since it's not possible to see the rows in db?
You can read the technical details of it here: https://github.com/craftcms/cms/issues/1507#issuecomment-633147835
Craft no longer keeps track of element queries needed for cache invalidation in the database, but they are stored in Craft's data caches
Craft::$app->getCache(), which uses the file system by default and it uses more of a tag-based cache invalidation strategy (similar to https://plugins.craftcms.com/cache-flag if you've ever used that).