How to Safely Install Windows on a Separate SSD Without Affecting Linux?

Once you have both OSs installed, you can use 'msconfig' in Windows to manage the boot menu for dual booting. You can set your default OS and choose the timeout settings as well. If you switch between them often, consider running one OS in a VM on the other. Just keep in mind that configuring a Windows VM can be tricky if you want to use hardware passthrough.

Your plan sounds solid! Nowadays, Windows typically doesn't interfere with EFI partitions like it used to. UEFI ensures that only necessary EFI files are affected. The risk of losing configurations is more about weak nvRAM on your motherboard, not Windows causing chaos. In theory, you could just use one EFI partition without any issues.

I'd recommend doing the same thing for Linux — disconnect the Windows drive during its installation to prevent any EFI conflicts. Some Linux distros have had bugs in the past that might cause misconfigurations, so it’s safer to keep them isolated at first.

Honestly, dual-booting can be a hassle. If it's feasible for you, I’d suggest installing Linux and running Windows in a VM or using something like VirtualBox instead. It simplifies the whole process!

If your laptop has two SSD slots, just pop in the new SSD and select it during the installation. This way, Windows will create its own separate EFI partition. After installation, you can easily choose your OS to boot by hitting Esc, F10, or F12 during startup. Both systems will remain unaffected with their own EFI partitions.