Install without networking, internet or Microsoft account.

Take plenty of time and get accustomed to going through every single setting in Windows to become familiar with what you're up against, and craft the dozens of privacy- and performance-compromising options specifically for your intended use case, while cutting back on the lingering or lurking annoyances all over the place.

For instance I have a very different approach when I am going to use a PC for scientific software connected to a laboratory instrument, versus using a different PC as an office machine, or as a gaming machine. Then further optimized configurations for any of the above which are intended never to be connected to a network and/or internet, or as reference PC's for which any "updates" can be undesirable.

This is a little bit of a simulation of how it used to be for scientific instruments before the internet arose. But back then all you had to do was reconfigure those Windows settings where the general office-oriented defaults were unsuitable for specialized performance. There was no need to tame an ever-expanding behavior-tracking, advertising component back then. A lot has changed in 30 years, for those of you who thought WIN.INI was bad enough. Windows now needs more tweaking than Linux and it's accelerating each year while Linux is becoming more suitable for more people right out-of-the-box all the time.

If you got really ambitious and have the patience with Windows, you could take the time to document every single step, but with enough familiarity otherwise you will find it helpful to mentally recall which settings you might want to remember to revert to default occasionally for certain particular situations or apps.

All before going on the internet. Then reboot to the Windows Startup USB stick, go to the Command Line (not To Install again) in order to access your main (now dormant) Windows partition from elsewhere, and get your external backup storage ready (or use the USB stick itself if it has enough free space). Then back up your carefully-crafted Windows platform sitting there in its virgin condition before even using it for anything productive, employing DISM.exe from the command line to /capture-image from your entire main Windows volume to a .WIM file named the way you want, to be stored on your backup drive in your choice of folders. If you haven't installed any of your usual user software or gone online to download anything, the WIM file will be something like about 10GB in size or so at the default compression. Takes about 5 minutes on a nominally-powerful PC.

This WIM file of a complete Windows install can then be Applied ("restored") to a different-sized NTFS-formatted partition as long as there is enough space for the fully expanded Windows fileset. If the target were to be a differently located partition, you would have to create specific bootfiles to accomodate that using BCDBOOT.exe and likely benefit from some bootloader editing using BCDEDIT.exe, which can also facilitate straightforward multibooting if so inclined.

Once the Windows partition has been backed up as a WIM file, then shut down, remove the USB stick, and reboot to Windows like normal.

Now you can install any needed updates, drivers and/or software and begin to bloat Windows for your own purposes. Without much fear if things go wrong, since booted externally you can always restore Windows to an empty volume from its backed-up WIM file, back to the same virgin Windows install with all of your specific tweaks intact just like you left them. Which can save hours compared to a fresh install. Deployment using DISM only takes a few minutes itself and /apply-image is more or less the opposite of /capture-image.

Once you get your programs and drivers successfully in place you can then boot to external media again and capture an even bigger WIM file as a complete volume snapshot of that particular milestone . . .