Just gonna share a tool I found recently that is really awesome for making debs, Debcraft (https://salsa.debian.org/debian/debcraft). It uses podman to isolate the build environment. The author of OP is also a major contributor, even though he barely mentions Debcraft in the post.
sbuild is the tool used by the Debian community and all the Debian infrastructure to do this. Uses schroot under the hood, and is what you want instead of docker and friends 99% of the time anyway.
Both sbuild and Debcraft essentially still run a minimal hermetic Debian environment without network access inside them. The fact that sbuild exists is not a reason to not try out Debcraft. However the selling point in Debcraft is not that it has the build environments, but much more.