Apple has stopped providing standalone updaters in macOS Big Sur
Apple has stopped providing standalone updater versions of its macOS system software, starting with macOS Big Sur 11.0.1 -- but is still providing them for Catalina and Mojave as recently as December 16.

Credit: Andrew O'Hara, AppleInsider
For decades, Apple has offered a users the ability to download standalone smaller update files without needing to download a full OS install image, or the same update in the macOS Software Update feature multiple times across a rollout of Macs. In macOS Big Sur, that download has not been made available for any of the updates.
As noted by The Eclectic Light Company, Apple has yet to release a standalone installer for macOS 11.1 much less 11.0.1, despite releasing standalone installers for macOS Catalina and Mojave security updates on Dec. 16.
AppleInsider has confirmed that this is the case. Sources within Apple corporate not authorized to speak on behalf of the company point to content caching options available in macOS as an alternative to prevent multiple Internet downloads. However, this does nothing for administrators that want a mobile update file on external media, or similar deployment.
According to Mr. Macintosh, Apple is advising users who need individual downloads to contact them in an "official capacity" to hope to change Apple's point of view on the matter.

Credit: Andrew O'Hara, AppleInsider
For decades, Apple has offered a users the ability to download standalone smaller update files without needing to download a full OS install image, or the same update in the macOS Software Update feature multiple times across a rollout of Macs. In macOS Big Sur, that download has not been made available for any of the updates.
As noted by The Eclectic Light Company, Apple has yet to release a standalone installer for macOS 11.1 much less 11.0.1, despite releasing standalone installers for macOS Catalina and Mojave security updates on Dec. 16.
AppleInsider has confirmed that this is the case. Sources within Apple corporate not authorized to speak on behalf of the company point to content caching options available in macOS as an alternative to prevent multiple Internet downloads. However, this does nothing for administrators that want a mobile update file on external media, or similar deployment.
According to Mr. Macintosh, Apple is advising users who need individual downloads to contact them in an "official capacity" to hope to change Apple's point of view on the matter.
Manual downloadable delta and combo updates for Big Sur are no longer available. I will let our resident #MacAdmins expert explain
"If you have a need for individual downloads for Big Sur delta/combo updaters - please make sure that's filed in an official capacity with us"-- Mr. Macintosh (@ClassicII_MrMac)
Comments
If you haven’t installed it yet you probably never will because of the question you asked. You want bug free software but it doesn't exist and never has.
And by the way, who do you accept as an authoritative source to tell you it’s okay to install Big Sure?
And yes @pulseimages, it seems to be in a good place to me. Ymmv depending on your specific setup and needs of course.
This is so strangely put
Multiply this by a dozen machines, and it's a lot of time.
It isn't the end of the world. But, it is a big deal for enterprise and other rollouts, particularly ones that have air-gapped installs and the like. The DoD isn't pleased about it, for instance.
He has a valid point. Incredibly stupid to ask 'are all the bugs worked out yet'. Software always has bugs. If the guy had a clue, he could install on an external drive and test his software to see if he encounters anything critical. If not, then he can decide to upgrade. Totally dumb to ask in any group...are all the bugs gone because I refuse to download it and test it on my own. The guy should not own a computer if that is his mentality.
The worst was the introduction of the T2 chip which by default prohibits you from installing macOS on your own system, without jumping through hoops (when you want to do a clean-install). The default is to only allow a macOS install from the Command-R recovery mode, requiring a long download. By default, you cannot boot from any external drive, unless you specifically disable the restriction that prohibits external drives. Also, you have to allow macOS install from any source. If you do not change those settings and you wipe the drive to re-install from an external USB boot disk, you can brick your Mac if you do not have internet access to re-install macOS.
Also, the creator of Diskmaker X has 'retired' the product because he does not have the time to re-write the program to figure out how to make a Big Sur boot disk with all of Apple's changes. He never could get it to work running Catalina. So the only way to make a Catalina boot disk is to run it from Mojave. So I am guessing it is nearly impossible to make a USB boot disk of Big Sur.
Been using happily using both since release.
You can also follow Apple's instructions that require Terminal (https://support.apple.com/en-us/HT201372),