You're aware and take advantage of the zsync too I hope...
eg. I run a script to update my ISO, it'll include the commands
wget http://cdimage.ubuntu.com/ubuntu-mate/daily-live/current/resolute-desktop-amd64.iso.zsync
zsync -u http://cdimage.ubuntu.com/ubuntu-mate/daily-live/current/resolute-desktop-amd64.iso resolute-desktop-amd64.iso.zsync
ie. it'll download the .zsync file fully (~8.2MB currently) and then use that to update my current ISO by downloading the changed sections of it.
I actually also wget the manifest as well; and for the first download of the cycle I start with the questing (or a prior ISO) too that I've copied and change the name to the reflect new codename, so I'm not even downloading the whole file even that first ISO download for a development cycle.
I just did a check; if you start with a 25.10 ISO you'll start the download with 35.4% complete; with only CPU & local disk used in that calculation (and small zsync file I mentioned earlier)... but if you start with your newer 20251119 ISO you'll have far less to download than the 20251007 ISO used in my 35.4% [starting point] comparison I'd bet.
Later addition: A zsync tutorial was added to this site; refer Ubuntu MATE daily iso painless update script