Last night mine managed to download all 508 of 508 files, but then got stuck decompressing one of them (fspackage.25).
The installer appears to delete each fspackage it has already decompressed. This means when I restart the installer today it’s trying to re-download fspackages 1-24 even though I already have the contents of those decompressed.
Download speed isn’t directly the issue for me it seems, but a decompression one. Memtest, drive space etc. all fine, so not sure what else I can do. Presumably a VPN won’t fix a buggy decompression step.