The wolfram-engine package is available from the official repository
https://archive.raspberrypi.org/debian/pool/main/w/wolfram-engine/wolfram-engine_13.3.1+20230814893_arm64.deb
and can be simply installed or updated using the built-in package manager (apt).
❯ sudo apt update
❯ sudo apt install wolfram-engine
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
wolfram-engine is already the newest version (13.3.1+20230814893).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded
That said, I do get a install-wolfram-engine-13.3.1.sh file after clicking the manual installation link at https://wolfr.am/raspi-install, so perhaps there is some cache somewhere that needs to be cleared.
