Adsense does not display ads on dynamic pages.

[Hashigato]

I have dynamically created the URL structure of my website for enlarging Instagram profile photos. When a user searches for any Instagram account username, the results are shown under this URL: https://site.com/fullsize/username. As you can see, the username parameter here varies for each Instagram account. My website has been active with AdSense for almost a year, but ads are only displayed on pages indexed by Google. When a new user is searched for and the page is not yet indexed by Google, ads are not shown to the user. Some websites that offer Instagram profile photo services operate on the same logic, yet they display ads on every page. How can I solve this issue? Would changing the dynamic page structure to use POST instead of GET method help? For example, instead of showing each user's result on a different URL like https://site.com/fullsize/username, if I display them all on the /fullsize page using the POST method, would that resolve the problem?