Control AVPlayer stream buffer size for completely offline playback

I am doing CMAF/HLS video streaming on AVPlayer. The player downloads the future .ts/.cmfv chunks during buffering, but after a certain number of downloads, if I seek back to the start, it redownloads the chunks, which is unlike the web where all the chunks are taken from the cache due to bigger cache size. How do I increase the buffer size so that I can cache the entire video, the size of which is around 90-100MB?

I tried using the oft-mentioned preferredForwardBufferedDuration property, but it just changes the number of chunk calls for the future, but if I get back to the start after a long enough playback time, it re-downloads the stream chunks all the same.