Debian terminal not displaying correct Unicode half-block characters

Question

I have a program that prints Unicode half-block characters (U+2580, U+2584), but on Debian 10 terminals (just the fullscreen terminal, no X), it's printing diamonds instead of half-blocks.

The two images below are the output of a Python program...

import sys
print(f"character encoding: {sys.stdout.encoding}")
print(chr(0x2580)) # upper half block
print(chr(0x2584)) # lower half block
print(chr(0x2588)) # full block

...followed by the output of locale.

macOS / SSH (correct)	Debian (diamonds)

Also here are the contents of /etc/default/console-setup:

admin@flipdisc:~$ cat /etc/default/console-setup 
# CONFIGURATION FILE FOR SETUPCON
Consult the console-setup(5) manual page.
ACTIVE_CONSOLES="/dev/tty[1-6]"
CHARMAP="UTF-8"
CODESET="Lat15"
FONTFACE="Fixed"
FONTSIZE="8x16"
VIDEOMODE=

I've noticed that:

• The macOS Terminal application prints the half-blocks correctly.
• When I SSH to the Debian machine in the macOS Terminal, it also prints the half-blocks correctly.
• The Debian terminal prints diamonds.
• I have a few other Debian machines and they also all print diamonds.
• The Debian terminal does print full blocks correctly, for some reason.

The locale output identifies en_US.UTF-8 for both machines, and I'm not sure what else to check.

So my questions are:

• Why is the Debian terminal printing diamonds instead of the correct half-block characters?
• How do I make it print the correct characters?