Functionality of the --dev-flag/can't enter bwrapped namespace due to nesting (opt_needs_devpts)

So, I've been using bubblewrap to isolate environments and I've been using the "--dev" option to populate /dev in the mount namespace.
Unfortunately I can't enter the created namespaces with nsenter (as a normal user); I think this is related to the --dev-option binding stdout of the process to /dev/stdout. What are the considerations of this when comparing it to setting up a tmpfs and linking the relevant dev (null/random/...)?

Considerations are: terminal won't work ;).

This seems really weird. Removing all the code in the case-statement for "SETUP_MOUNT_DEV" also does not work.