What parameters could be used to test an encryption library

I've written an encryption library using Typescript and webcryptoapi. For reporting purposes I need to make some mathematical performance analysis of the protocol.

For demo purposes, I've created a simple HTML page with couple of text boxes and encryption, decryption button as well couple of labels to show auxiliary data helping to encryption and decryption.

However, Webcryptoapi, runs locally inside the browser, thus no api call is made. Hence, I'm kindly asking you what kind of performance test I could apply? So far I measured the durations for key derivation, encryption and decryption. In addition, I estimated a possible data usage. However, because it is one javascript file, I dont have a chance to see big differences in memory usage and so on. If anyone could give me further ideas about what I could test, I would appreciate it so much