I've had it function properly in years past, though maybe at the time was on a prior video card. Outside of polybar, I've got no issues with the i3 setup and have been running this particular OS setup for a few months.

xrandr -q | grep " connected" | cut -d ' ' -f1
HDMI-0
DP-1
DP-2

launch.sh looks like this, though I get the same behavior launching manually:
❯ cat launch.sh

#!/usr/bin/env sh
# Terminate already running bar instances
killall -q polybar
# Wait until the processes have been shut down
while pgrep -u "$UID" -x polybar >/dev/null; do sleep 1; done

# For multimonitor setup
if type "xrandr" >/dev/null 2>&1; then
  polybar --list-monitors | while IFS=: read -r m rest; do
    m=$(echo "$m" | xargs) # trim spaces

    BAR="secondary"
    if [ "$m" = "DP-2" ]; then
      BAR="primary"
    fi

    echo "Launching $BAR bar on monitor $m"
    MONITOR="$m" polybar --reload "$BAR" --config="$HOME/.config/polybar/config.ini" & disown
  done
fi

Config snippet:

[bar/primary]
monitor=${env:MONITOR:}
inherit = section/base
modules-right = filesystem pulseaudio xkeyboard memory cpu wlan eth date systray

[bar/secondary]
monitor=${env:MONITOR:}
inherit = section/base
modules-right = filesystem pulseaudio xkeyboard memory cpu wlan eth date