Thanks, but unfortunately Apple appears to have removed all Ventura 13.6.x InstallAssistant packages from their catalogs/CDN already, so I haven't been able to find them on swcdn.apple.com anymore.
I see what you mean. I thought that since the links are still available that the files would still be accessible.
You might try internet archive as well
I checked internet archive and using the keywords Ventura install assistant, I was able to see packages for 13.6.4, 13.6.5, 13.6.6, and 13.6.7
UPDATE: The reason I wanted to try to install macOS 13.x on my MacBook Pro 2015 was to have AirDrop detect devices running older operating systems. When my MacBook Pro 2015 was running macOS 15.7.x it can only detect my iPhone 11 Pro Max running iOS 18.7 while the iPhone 7 Plus running iOS 15.x and the iPad 6 and iPad 9 both running iPadOS 16.x were not.
Unlike my experience when installing macOS 15.7 using open core 2.4.0 which automatically pops up after successful macOS installation, I had to download open core from Github and thankfully, Wi-Fi was working on macOS 13.x so I just had to connect to the network, install open core and apply root patches.
Now that my MacBook Pro 2015 is running macOS 13.7.8 it is now able to detect the iPhone 7 Plus running iOS 15.x and the iPad 6 and the iPad 9 both running iPadOS 16.x while still detecting the iPhone 11 Pro Max running iOS 18.7
The iPhone 7 Plus and iPad 6 and iPad 9 all can now send and receive files to and from the MacBook Pro 2015 while the iPhone 11 Pro Max can still be detected by the MacBook Pro 2015 despite downgrading macOS. I don't know what it is about macOS 15.7 but only the iPhone 11 Pro Max was detected during AirDrop. I haven't tried macOS 14.8 to see if the same thing will happen but I'll just stick with 13.7 at this time.
I just have to install macOS 15.7 on another partition/disk so that apps from the Mac App Store that cannot be downloaded on macOS 13.7.x because they require a newer macOS release can be downloaded again.
I still have the App Store links for version 14.5 of Keynote, Numbers, and Pages but when you paste the web links on a browser, they are no longer available. I can download the Creator Studio versions [using macOS 15.7] but I don't know if I can download the Ventura compatible versions. I guess I'll just use LibreOffice instead.