Browser compatibility of FileSaver vs sending file from server using Content-Disposition: attachment

This is a general question about which method I can expect to have greater browser compatibility (specifically with iOS Safari).

Both options are available to me, although I'd prefer not to involve my server.

The reason I ask is because FileSaver works on the two iOS devices I've tried, but some other iOS users report that my download functionality doesn't work for them.

Will I have greater browser compatibility sending file from server using Content-Disposition: attachment, or is FileSaver still my best bet?

(This is for downloading images and videos stored in an AWS S3 bucket.)