Yes, there currently is no way to unlock the badges for the non-connectable devices at this time. There is a wishlist item here for activating the non-connectable badges.
I use the night light lights for the same reason on staircases. At first I had them synced them but as you mentioned the batteries do drain faster when synced. I moved to unsyncing them and found that while they all didn’t light up at once, they light up enough for me to see when needed and extended the battery use. Maybe worth a try to extend the battery.