Why do dynamic checkout buttons load slowly on my product page?

To give a better solution it would be helpful to check your store and run several tests but according to your description what I can tell you is, if you are using apps to show those buttons it might be due to the apps as they take some time to load.

If it is due to the liquid you can check it using google page speed insights.

For a more detailed review, you can visit our website and submit your store.