Is it possible to downgrade to macOS Big Sur 11.0.1?

Does Apple still offer the full installer for macOS Big Sur 11.0.1? If not, is there any other way to obtain it (other than using the 11.0.1 IPSW file)?

Background: I recently got an M1 Mac mini (base model) to explore the system architecture of M1. Currently, I have two copies of macOS 11.1 installed on the internal drive. I'm trying to downgrade one of the installations to 11.0.1 as part of testing the Reduced Security mode. Erasing only the target installation is fine; however I'm trying to avoid erasing the entire drive (which is what an IPSW restore would do).