MacOS Catalina on Unsupported Macs

Need some help from someone who understands using dosdude1 Catalina patcher.
When running Catalina on an unsupported Mac, my experience has been the OS does not do any Apple provided updates. I installed 10.15.1 several months ago, and it never showed any updates, including security updates.
Also, I never got any offers to update to 10.15.anything.
So, I decided to download the patcher again, create install drive, and install it. I expected that I would end up overwriting the existing 10.15.1 install, and have to start from scratch.
When I booted to the install drive, got a MacOS Repair menu. One option was to re-install all patches, and one was to install the OS. Tried the patch option first, to see if this would do a “normal” update, but it said it would install them on my Bootcamp drive, so I cancelled.
Then I choose Install MacOS, expecting a complete overwrite.
When it finished the install, it booted up in 10.15.4, with all my existing data and configuration.
So, am I correct in thinking I will not get any Apple OS updates running the patcher version, including security updates?
And, can I be confident that when dosdude1 offers any updates to future 10.15 versions, I can run the patcher install process, and my system will update without deleting my data and configuration?
And, is there anywhere that actually documents how to update the OS and what to expect?